Messi scored his 599th and 600th goals for Barcelona to subdue a Liverpool lineup that had outplayed the hosts for long stretches at Camp Nou on Wednesday but finally succumbed to the Argentine's mastery.
His double and Luis Suárez' early goal against his former club gave Barcelona a commanding 3-0 win in the first leg of the Champions League semifinals. Messi has won the Champions League four times but his hunger to restore Barcelona as the best club team on the continent was evident against Liverpool, when he had to almost singlehandedly quash a ferocious comeback attempt by the visitors after Suárez' 26th-minute opener.
Messi doubled the lead from a rebound with 15 minutes left and followed that up by curling in a perfectly struck free kick in the 82nd. Mohamed Salah nearly scored a valuable away goal for Liverpool to take back to next week's return leg at Anfield when he hit the post late.
"It is not over because we are going to a ground that is very difficult, with lots of history, that presses rivals, but we are happy with today's game," Messi said. "This is the critical moment, the best moment, and we have to be more united than ever. At the start of the year we said we would do this together."
Messi's double also took his overall tally for the season to 48 goals and his Champions League-leading tally to 12 this campaign. It was a bitter loss for Jürgen Klopp's Liverpool, which is trying to reach consecutive European finals after losing last year's decider to Real Madrid.
Even though striker Roberto Firmino was only fit enough for the final 12 minutes, Liverpool dominated long stretches of the match but failed to finish its chances. "I think that it was the best we have played in the Champions League, including last year," Klopp said. "We had good chances and caused them real trouble. The problem is that we didn't score a goal."
On Tuesday, Ajax won 1-0 at Tottenham in the other semifinal. Barcelona has already clinched the Spanish league title, leaving it free to fully focus on the second leg while it aims for a rare treble of titles.
Liverpool doesn't have that same luxury, being in a race with Manchester City for the Premier League. It trails City by one point and visits Newcastle on Saturday. The speed of Salah and Sadio Mané caused Barcelona problems throughout and a flurry of jitters in its backline.
But Messi was a force at the other end, making Liverpool's defense bend and almost break on his solo runs until it finally gave way in the final minutes. "He was unstoppable," Klopp said. When a lull in the action came after a frantic start, Barcelona found a way through to break the deadlock.
Defender Jordi Alba sent a perfectly weighted long pass that was reminiscent of the best assists of former Barcelona great Xavi Hernández. The ball skipped past a backtracking Virgil Dan Dijk and met the run of Suárez, who slid and used the tip of his right boot to tuck the ball home.
Liverpool pressed Barcelona into its area after halftime and succeeded in the rarest of football feats: taking the ball away from Barcelona. James Milner and Salah drew the saves from Marc -Andre ter Stegen just after the restart. Milner then wasted a golden opportunity when he fired into Teg Stegen's arms.
That was when Messi settled the match. "We played their game, at their physically demanding pace," Messi said. "We aren't used to that. We like having possession of the ball. We were exhausted, but that's what the match demanded."
Messi's first goal came with a bit of luck after Suárez kneed a volley against the bar and the ball fell straight to Messi, who chested it down and tapped it into an empty net. The second was spectacular. After he was fouled by Fabinho well outside the area, Messi struck a swerving, left-foot strike past a diving Alisson and into the corner of the net.
"We know what Messi can do but he does not stop surprising us," Barcelona coach Ernesto Valverde said. "He has made the difference again and pushed us to victory."
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