The Real Madrid players kept their cool despite conceding a stunning early goal in the Champions League, producing an outstanding performance that kept the defending champions on track for a seventh straight appearance in the quarterfinals.

Madrid rallied to defeat Napoli 3-1 in the first leg of the Round of 16 on Wednesday. Karim Benzema, Toni Kroos and Casemiro all scored after Lorenzo Insigne's extraordinary goal for Napoli less than 10 minutes into the match at Santiago Bernabeu Stadium.

The Italian forward struck an unexpected shot from way outside the area, catching Madrid goalkeeper Keylor Navas out of position. But the visitors couldn't hold on to their lead against a Madrid team that delivered one of its best performances for weeks.

"We played a great game," Madrid coach Zinedine Zidane said. "It was a shame about the Napoli goal, but we recovered, scored ourselves and turned the game around."

"I'm happy with the result," Zidane added, already looking ahead to the return match on March 7. "We'll go there to a difficult ground where we'll suffer. It's still an open game. We need to go there and finish it off."

Playing in the last 16 for only the second time, Napoli was one game short of equaling its unbeaten record of 19 matches in all competitions. It hadn't lost since a 2-1 defeat by Juventus in Serie A last October, a streak that included 12 victories.

"We faced the best team in the world, but it's a pity that we made so many mistakes with the ball because we usually don't do that," Napoli coach Maurizio Sarri said. "I think Madrid played their best game in three months, while we were not at our best tonight — We can compete with them if we play our best football."

Madrid, which won its 11th Champions League title last season, extended its streak without a home loss in the European competition to 12 matches.

With former great Diego Maradona supporting from the tribunes, and nearly 5,000 fans loudly cheering from the stands, Napoli made an ideal start with Insigne opening the scoring with his superb long-range strike in the eighth minute.

He received a through-ball from captain Marek Hamsik and struck a first-time shot from about 30 meters (yards) out to catch Navas off-guard. The ball bounced once before hitting the net near the far post as Navas desperately tried to recover.

"Despite the result, I think we played a good game," Insigne said. "Now we have the return leg at the San Paolo Stadium and I'm sure that we will fight even more. Real Madrid are the world champions, a team with 18 phenomenal players in their squad, (but) I did not see such a huge difference as the result would suggest. Maybe we made too many mistakes — this will only push us to work even more."

Benzema leveled 10 minutes later with a header after a cross by Dani Carvajal from the right flank, scoring his first goal in six games and surpassing Thierry Henry as the French player with the most goals in Champions League history with 51.

Benzema, Madrid's top scorer in this season's Champions League with five goals, almost added another in a breakaway just before halftime, but his attempt struck the post.

Kroos put Madrid ahead from just inside the area in the 49th minute after Cristiano Ronaldo cleared a defender to set up the German midfielder. Casemiro sealed the victory with his perfectly struck volley from outside the area in the 54th, hitting the far corner.

Napoli had a goal disallowed for offside in the 80th.

"There is still a lot left to do," Casemiro said. "We know that they are dangerous when playing at their stadium. We have to maintain our calm and our focus."

Ronaldo had a great chance to score in the 28th minute, but his shot from close range sailed over the crossbar.

The star forward remains two goals short of becoming the first player to score 100 goals in European competitions. He is the Champions League's leading scorer with 95, two more than Messi.

Bayern Munich answered its critics with a comprehensive 5-1 rout of Arsenal in the first leg of their Champions League clash to move a step closer to the quarterfinals on Wednesday.

Thiago Alcantara struck twice in a superb performance, and Arjen Robben, Robert Lewandowski and substitute Thomas Mueller scored the other goals.

The return match is March 7, when Bayern will be a hot favorite to advance.

"It's a very, very good position," Bayern captain Philipp Lahm said with a smile. "It should do."

Arsenal, which lost captain Laurent Koscielny to injury early in the second half, appears set to exit in the Round of 16 for the seventh season in a row.

"The real problems came after the third goal, because we lost our organization and looked really jaded," Arsenal coach Arsene Wenger said. "The last 25 minutes was like a nightmare for us because we had no response."

In the night's other first-leg match, Real Madrid rallied from a goal down to beat Napoli 3-1 in Spain.

Bayern extended its winning run at home in the competition to 16 games with a repeat of the score from the last time the sides met in November 2015.

"It's only one game," Bayern coach Carlo Ancelotti said, playing down the significance of the win. "It's not the final, unfortunately."

But Ancelotti will be relieved his side showed what it is capable of after five unconvincing games since the winter break, when Bayern faced criticism for looking tired and lacking the dominance it displayed at the start of the season.

There was little Arsenal goalkeeper David Ospina could do to stop Robben from opening the scoring in the 11th minute. Given too much space, the Dutchman cut inside as he's done so often before and let fly with a shot that went in off the underside of the bar.

Bayern dominated, and it seemed only a matter of time before the home side would add to its tally. Instead, Arsenal was given a lifeline when Lewandowski took down central defender Koscielny and the referee awarded the penalty before the half-hour mark.

Amid deafening whistles from the home fans, Manuel Neuer saved Alexis Sanchez' weak spot kick. Sanchez missed the rebound, but cut the Bayern fans' cheers short when he prodded in at the third attempt.

Suddenly the momentum was with Arsenal. Granit Xhaka should have scored when he shot straight at Neuer, and Mesut Ozil might have made it 2-1 at the break, only for Neuer to come to Bayern's rescue again.

But it was all Bayern after Arsenal lost Koscielny in the 49th minute.

Robben and Lahm combined on the right ring, the latter producing an inviting cross for Lewandowski to rise above two defenders and head inside the right post in the 53rd.

The Poland striker produced a brilliant back-heeled flick to send Thiago through to score another three minutes later.

Bayern had a host of other chances, first through Lewandowski, who struck the crossbar after rounding the 'keeper, and then through Robben, who was blocked by Kieran Gibbs, illegally according to the Bayern players, who demanded a penalty.

Those claims were forgotten when Thiago scored his second, minutes later, with a deflected shot after a corner, before he set up Mueller to complete the rout with two minutes remaining. The Germany forward had come on two minutes before.

"We have to cope with the result," Wenger said. "No matter what we say now, it's detrimental to us."