Arsenal manager Arsene Wenger's surprise decision to drop star player Alexis Sanchez backfired as Liverpool won 3-1 in the English Premier League to reignite its ambitions of Champions League qualification on Saturday.
Sanchez, the league joint-top scorer with 17, was left on the bench until halftime — by which time a rampant Liverpool side was 2-0 ahead at Anfield thanks to goals from Roberto Firmino and Sadio Mane.
Arsenal was much improved with Sanchez on the field and he set up Danny Welbeck's goal in the 57th minute with a pass through the heart of Liverpool's defense.
Liverpool sealed victory in stoppage time through Georginio Wijnaldum's goal on the break to clinch only its second win in eight league matches in 2017. It lifted Juergen Klopp's team into third place in the fight to reach the Champions League.
Arsenal dropped out of the top four on another tough day for Wenger, whose future at the club is up in the air with his contract over at the end of the season. His decision to leave out Sanchez will be debated long and hard and was clearly a mistake, considering the impact the forward had when he came on.
Wenger said he selected Olivier Giroud over Sanchez as the starting striker to offer a direct, physical option in attack. Quite why he dropped him completely, instead of simply playing him out wide instead, was startling considering Sanchez's importance to the team.
Wenger said he had no regrets.
"Everyone will come to the same conclusion but I am strong enough and lucid enough to analyze the impact and I don't deny Alexis Sanchez is a great player. I bought him and I always played him, and think he developed well with us," Wenger said.
"A decision like that is not easy to make, you have to stand up for it."
With playmaker Mesut Ozil also missing because of illness, Arsenal's starting lineup was lacking star quality — and perhaps a sign of things to come next season — and was picked apart by Liverpool in the first half.
Slicker with its passing and faster to the ball, Liverpool cut through Arsenal repeatedly and went ahead when Mane's skewed shot from the right was missed by Coutinho and went straight through to Firmino at the far post. Firmino took a touch and fired high into the net from close range.
He repaid the favor in the 40th. He collected Wijnaldum's inside pass, turned Francis Coquelin and opted against shooting to slide a pass across to the unmarked Mane, who lashed in a low angled drive.
So poor was Arsenal that its fans chanted sarcastically "We've had a shot" after Granit Xhaka blazed a long-range effort over the crossbar toward the end of the half.
Sanchez's introduction at halftime completely changed the game. Arsenal was suddenly more dangerous with its 17-goal forward on the field and Liverpool finally had an opponent to fear.
Stationed on the left wing, Sanchez ran at Liverpool's defense immediately and the atmosphere became tense. He showed great vision by playing a ball through for Welbeck, who chipped over advancing goalkeeper Simon Mignolet.
The game was in the balance until the first minute of injury time, when Divock Origi was set free down the right and the substitute crossed low for Wijnaldum to steer home a calm finish.
Manchester United wasted its chance to leapfrog Liverpool and Arsenal into the top four of the Premier League after being held 1-1 Saturday by 10-man Bournemouth.
United dominated from the start at Old Trafford and went ahead through Marcos Rojo in the 23rd minute before Joshua King equalized in the 40th.
Andrew Surman was sent off just before the interval with a second yellow card but the visitors held out afterward.
Bournemouth goalkeeper Artur Boruc saved a penalty kick in the 72nd from Zlatan Ibrahimovic.
United stays sixth with 49 points, the same as fifth-placed Liverpool which hosts fourth-placed Arsenal later Saturday.