England edged Ireland 13-10 in a test of breathless intensity at Twickenham to open up the Six Nations into a four-team race at the halfway point on Saturday.

Ireland was the last unbeaten side in the championship after France fell to Wales on Friday, and was favoured to end a three-match losing run to England with a side with more than twice as many caps, rampant momentum, and added incentive to celebrate Brian O'Driscoll's world record-tying 139th test cap.

But England, with unexpected daring, overturned a 10-3 deficit to lead again within eight minutes, and more than a quarter of the match to go.

In a match marked by gritty, desperate defence, the young English withstood a firestorm finish from Ireland to register what coach Stuart Lancaster called the best win in his tenure, considering the context.

"Given the experience of the Ireland team, the form they were in, the quality of the coaching and the players they've got and some of the relative inexperience we have, I'm just so proud of the boys," Lancaster said.

"We showed great maturity in closing out the game. It was character, spirit, playing for the shirt. Ireland, fair play to them, threw everything at us, and once we got that lead we just clung on in there."

Four teams were tied at the top, with Ireland ahead only on points difference from England, Wales and France.

The next decisive matches appeared to be England hosting two-time defending champion Wales in two weeks, and France closing the tournament at home against Ireland.

England and Ireland scored one converted try each, with the difference on the scoreboard provided by England's Owen Farrell, who knocked over two of his three penalty attempts. Jonathan Sexton hit the only penalty shot he had.

Ireland's scrum was dominant, taking advantage of England tighthead David Wilson playing with basically only a half of rugby in two months. But for all of the ball Ireland had, it couldn't turn pressure into points as England's defence and discipline was top shelf.

England fired the first shot in the thriller. Left wing Jonny May should have crossed in the right corner early but he was slowed by Ireland flanker Peter O'Mahony and scrumhalf Conor Murray arrived just as May was diving over the line to knock the ball from his grasp.

Then Ireland worked a brilliant move, with Sexton's crosskick caught by Andrew Trimble on the right wing, but his offload inside to fullback Rob Kearney was bobbled, and he was swallowed by Englishmen.

Farrell was lucky soon after not to be sin-binned. His late shoulder charge on Murray conceded only a penalty. Referee Craig Joubert's decision was critical, because Farrell then kicked the only points of the half, a penalty from 50 metres.

Farrell's second penalty chance hit the upright, and the teams could both be happy where things stood at the break.

Just 90 seconds into the second half, Ireland was even happier.

Ireland worked lineout ball to the middle of England's 22, No. 8 Jamie Heaslip stood wide of a ruck and England believed he was spreading it wide. He was waiting for Kearney to scream up inside him, slice clean through and curve towards the posts untouched.

Sexton converted for 10-3, and added a penalty in the 49th for 13-3.

Then England turned on the pressure, and Ireland was happy to concede three points rather than five. Farrell obliged and the deficit was four.

England's try came from surprising ambition inside its own half. Farrell, under pressure in space, could have kicked the ball for relief but passed to Jack Nowell, who found Mike Brown inside speeding into a gap on halfway. Brown blew through, and scrumhalf Danny Care came up his inside to finish off between the posts. Farrell converted, England had the lead back, and this time kept it.

Wales beat France 27-6 to keep 6N title bid alive 

Wales gave a two-time defending champion's response to a demoralizing defeat by whipping France 27-6 and keeping its Six Nations title defence alive on Friday.

So shaken to the core was Wales by its 26-3 demolition from Ireland, the only unbeaten team left in the championship, that coach Warren Gatland warned his British Lions-laden side that careers were on the line under the Millennium Stadium roof.

The players' answer was a robust performance of power, pace and poise, adding up to a third straight win over France last achieved 42 years ago.

"That was the response we were looking for," captain Sam Warburton said. "We knew we had it in us."

He admitted playing for their jobs was also an incentive.

"We said in the week that we don't want to take our places for granted. We have probably worked our hardest in the last two weeks," he said.

Stand-in centre George North scored after five minutes and fullback Leigh Halfpenny's boot punished frequent French errors and a second-rate scrum with five penalties that propped up a 20-6 halftime lead. When Warburton reached out to plant the ball on the line in the 64th, the score became Wales' biggest win over France at home since 1950.

That margin will be vital in terms of points difference in the standings if Wales, which jumped over previously unbeaten France into second place, can stay on track and Ireland lose somewhere. The Irish are at Twickenham on Saturday.

Wales' performance wasn't assured beforehand, certainly not after lock Alun-Wyn Jones, who captained the Lions in their series-clinching win in Australia last year, withdrew just before the match with a foot injury. That gave a second Welshman, Jake Ball, his first test start beside scrumhalf Rhys Webb, whose zippy pass was a big factor in Wales' frantic start.

Five minutes in, lineout ball was spread left and inside centre Jamie Roberts drew two defenders. North gave Halfpenny an overlap and he chipped ahead. France fullback Bruce Dulin claimed the ball just before the tryline, but he was accidentally clipped in the head by teammate Jean-Marc Doussain and dropped the ball, which North pounced on in goal.

Halfpenny couldn't convert. He seemed to kick only the hardest goalkicks, and France kept giving him chances, especially from a scrum that Wales eventually got on top of.

Captain Pascal Pape conceded the second penalty from a ruck, and tighthead prop Nicolas Mas the third for slipping in a scrum. Wesley Fofana was milked by North in a ruck for Halfpenny's fourth, and a tighthead conceded just before halftime ended up giving Halfpenny his fifth penalty.

Moments before then, referee Alain Rolland told both captains the scrum was a mess and threatened to dish out cards. He upheld his promise in the 50th, sin-binning Mas and counterpart Gethin Jenkins. By then, Wales was in charge and the outmuscled French had few options.

"It was a catastrophic first half, our discipline was poor, and we gave away too many penalties," France coach Philippe Saint-Andre said. "We were totally apathetic in the first half."

Dulin said, "They got on top of us very quickly and we couldn't pull ourselves together. We didn't go about things the right way.

"We didn't start the game well and they just gained in confidence. After their match against Ireland they really wanted to put their foot down."

France had a try rightfully disallowed early in the first half for a knockon, but the backs received no ball and didn't go close again until the 50th, when centre Mathieu Bastareaud slipped North and was stopped just short of the tryline, and couldn't offload to Dulin or winger Hugo Bonneval.

The French backs were more involved in the second half, but Wales' defence was smothering. Frustrated No. 8 Louis Picamoles got himself sin-binned in the 62nd and Wales took advantage. From a Roberts barging run up the middle, Warburton charged off a ruck and just managed in a double tackle with an outstretched arm to put the ball on the line.

With 10 minutes to go, Wales substituted Adam Jones and Jenkins, Ball, Dan Lydiate, Webb, Rhys Priestland and Halfpenny, and all were cheered off as returning heroes deserve to be.

Duncan Weir's last-gasp dropped goal lifted Scotland over Italy 21-20 at Stadio Olimpico on Saturday for its first victory in this year's Six Nations.

Italy was heading towards breaking its own duck with a fourth straight home victory over Scotland after lock Joshua Furno's first international try, which replacement flyhalf Luciano Orquera converted with less than 10 minutes remaining.

But defeat left Italy winless through three rounds, while Scotland earned some redemption in rebounding from a 20-0 home loss to England, regarded as one of its worst displays ever.

"It's all a big blur to be honest," Weir said. "We had a few chances to go for it. I was in the pocket and 'Cus' (Chris Cusiter) gave me a lovely ball and the rest is history.

"You just have to go back to basics, get your ball drop right, and I managed to execute it. It's a great feeling and I am delighted for the boys we have come away with the win. We can kick on from here now."

With captain Sergio Parisse and prop Martin Castrogiovanni marking their record 104th caps for Italy, they were in the forefront in giving their side a deserved 13-3 lead at halftime. All of its points came from former Scotland Under-20 flyhalf Tommaso Allan, including his second international try.

Scotland upped its intensity after the interval, and centre Alex Dunbar scored two tries with Weir converting the second. Captain Greg Laidlaw missed one kick but weighed in with two penalties.

"The quality of the match was disappointing," Italy coach Jacques Brunel said. "It was the worst Italy I've seen since I've been here. We gifted Scotland the chance to win through our mistakes.

"We're behind in regards to our ambitions. I want to understand why we were so bad. We have to react. Our defence was good up until a certain point. But then ... we didn't do our part, we can put on very different performances."

Scotland conceded a third scrum penalty in the 12th minute and from that the Azzurri went on the attack.

As Italy punched at the tryline, roared on by the vociferous crowd, Allan forced it over but Robert Barbieri's pass was forward, and Italy came away with a penalty.

Scotland's indiscipline continued to grow, with the visitors conceding five penalties in the opening quarter — and that was to increase to 10 by halftime. However, Laidlaw evened the score with a penalty kick in the 23rd.

Scotland, which had one try in its last five matches in the Six Nations, had a great chance on the half hour when Weir broke in the Italian half but he cut inside instead of using Sean Lamont on his outside and slipped.

Allan put Italy back in front with another kick, and added his converted try in the final minute of the half, going over from Furno's pass after Sergio Parisse's charge off the back of the scrum.

Rather than deflate Scotland, the late score spurred the visitors to new heights in the new half. They put Italy under sustained pressure. The breach finally came in the 54th when Weir jolted the ball from Italy scrumhalf Edoardo Gori. Scotland spread it quick, and Dunbar sliced through and sped into the right corner to score Scotland's first try of the championship.

It took 12 more minutes to score its second. From a scrum on halfway, left wing Sean Lamont ran over Allan and Dunbar burst through. With Laidlaw off, Weir converted for Scotland's first lead at 18-13.

Italy looked to have rescued the win after a big run by left wing Leonardo Sarto up the middle, finished by Orquera and Parisse sending Furno over in the right corner for his first try in 16 appearances. Italy had a two-point lead.

But for the last few minutes, Scotland's forwards took control, busily working the phases, keeping the ball and making hard yards. With 19 seconds left, replacement scrumhalf Chris Cusiter fired the ball to Weir, who struck it sweet from 35 metres. He was already running back to his half in joy by the time the ball flew high inside the left post, the Stadio Olimpico stunned into silence.