Marcus Rashford struck the crossbar for the visitors in the second minute at the Nou Camp but Messi scored twice in the space of five minutes later in the first half to put Barca at ease, Reuters reported.
Philippe Coutinho’s stunning strike completed a dominant 4-0 aggregate victory.
“Messi always gets us out of trouble and we’re not going to apologize for having him,” Valverde told a news conference.
“Leo always turns up in the important games, not just in the big moments but throughout the whole game. He is always capable of scoring but he also drives the team’s attack.”
Valverde said his side was relieved to finally hurdle the quarterfinal barrier after three successive exits in the last eight, particularly after last season’s 3-0 second-leg defeat to AS Roma after winning the first leg 4-1.
“We had a lot of hope for this tie, it was a long time since we have been in the semifinals and we had a very painful defeat last year,” he said.
“You never know what can happen in football, they have a very good team and they could have caused us problems, so we made sure we were focused and played with intensity so we would make it through.”
United coach Ole Gunnar Solskjaer meanwhile backed Barca to conquer the continent again.
“With the quality they’ve got, the front three they’ve got, and players they can bring on like Dembele and Malcom, I wouldn’t bet against them,” Solskjaer said.
“They would be favorites to win the whole tournament.”
He added Messi’s majestic display underlined why is he regarded as the best player in the world alongside Cristiano Ronaldo.
“He’s an exceptional talent, he and Cristiano have been the best players in the world the last decade and he showed why we think that and why this team have won the Champions League so many times,” added the Norwegian.
“If you give him space and time around the goal he’ll create and score goals. Whenever he gets the ball around the box he will be decisive and unfortunately for us he was the winner for them.”
There was a huge sense of relief in Barcelona after brushing aside the recent Champions League quarterfinal failures, but Messi still criticized his side’s shaky start to the game.
“We cannot start like this in any Champions League game,” Messi told reporters.
“We said that from the start, we had the experience of Roma, you can’t afford to make life hard for yourself because one mistake can knock you out of this competition. We have to be aware of that.”
“We have become much more solid, over the season we struggled a little bit at the back but the whole team is making a huge effort and that makes it far harder for opponents to attack us,” Messi added.
“We had been three years without making the semifinals but we didn’t have any negative feelings. We knew we had a good scoreline, we’re happy to be in the semis but we must continue.”
Barca has not won Europe’s biggest prize since 2015 despite dominating the domestic scene in Spain and has had to look on enviously as archrival Real Madrid romped to three consecutive Champions League triumphs.
But there is now a sense in the Spanish media that everything is falling into place for Barca to reach the final at Atletico Madrid’s Wanda Metropolitano stadium in the Spanish capital on June 1.
“This is the year,” proclaimed Barcelona-based newspaper Sport, while Marca said “Messi flies toward the Wanda”.