Jurgen Klopp saluted the 'perfect reaction' of his substitutes after Liverpool beat Inter Milan 2-0 in Italy.
After a scoreless first period, Klopp withdrew Diogo Jota for Roberto Firmino due to an ankle injury before Jordan Henderson, Naby Keita and Luis Diaz were introduced around the hour mark.
After a sustained spell of pressure from Simeone Inzaghi's side, the Reds subs helped turn the game back the way of Klopp's team before Firmino headed in the opener from a corner.
Mohamed Salah then scored his 24th of the campaign to put the six-time European Cup winners in control ahead of the second leg at Anfield next month.
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Klopp was full of praise for how his subs helped steer the game away from the Nerazzurri, saying: "It was perfect how the boys reacted.
"All of them wanted to start, but coming on they have all my respect for Hendo's performance today and Naby who came on, Luis is so natural when he comes on too. So that is all very helpful.
"At half-time, when you can bring on Bobby Firmino, too. He needed time because he gets the balls in the most difficult areas in the centre when they come from all directions.
"He lost some balls but once he scored, all of a sudden you can see confidence coming back and the ball was our friend again. From there, we won the game.
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"During the game we didn't finish the situations often enough. Again a lot of their situations were offside and there was one where Atruo Vidal was offside.
"They gave them a corner from it and this rule is really... it will kill me one day!
"It was a clear offside, you can see it, and then they let it run and forgot to raise the flag in the end."
Klopp continued: "It was an incredibly physical game so I think we had to find a way.
"I think we started really well, we played around their formation in the beginning but they came up a bit with the direct switches to the wing-backs.
"We didn't defend that too well and too often our full-backs were alone in the one-versus-one situations - it doesn't work like that properly.
"In a game like this you have to keep the ball longer and that didn't happen often enough but you cannot come here and hope for a brilliant day and that is your only chance to get a result.
"We had not a brilliant day but a good enough day to be a deserved winner.
"We scored two wonderful goals and yes [Inter] had their moments with counter-attacks but mainly it was counters when we lost the ball in the wrong spaces. I am really happy."