Jurgen Klopp has explained the tactical switch that helped Liverpool towards the Liverpool send message to Barcelona and Manchester City with emphatic Porto win in Champions League
The Reds eased through to a last-four tie with Barcelona by earning a 4-1 triumph in Porto on Wednesday night to win their quarter-final tie 6-1 on aggregate.
However, Liverpool had to withstand strong pressure during the first quarter as the home side sought an early goal to spark hope of a comeback.
Why Jurgen Klopp believes Liverpool have just made a 'big statement' in Champions League
That was extinguished by Liverpool player ratings against Porto - Mohamed Salah and Sadio Mane star to set up Barcelona showdown 26th-minute away goal and a half-time formation change that saw Liverpool control the second period.
“I am very, very happy,” said Klopp. "I said it would be very difficult, so I knew it, and I can't be surprised it was difficult.
“They played a lot of long balls in behind, there were a lot of really physical challenges when as a defender you have to be a bit more careful because if you make a foul it's a free-kick and even worse a penalty.
“We had maybe not the best reaction on the second ball and they had the too many in the centre.
“We tried to change the system a couple of times and at half-time we moved to 4-4-1-1 and that helped, as we closed the centre better and it meant they couldn't switch the ball.”
The change also saw Divock Origi replaced at the break by Roberto Firmino, who went on to score along with Mohamed Salah and Virgil van Dijk.
Liverpool send message to Barcelona and Manchester City with emphatic Porto win in Champions League
“Bobby has no fitness issues and because he doesn't get any, that's why we started with Divock,” said Klopp. “We defended as a unit in the first line not too good, we had to change it at half-time.
“But it was nothing about Divock. In training he is in unbelievable shape. How the game developed was perhaps not the most thankful game for a striker. That’s all.”
Klopp added: “We had to defend in the first half hour a lot in the last third. That's okay. No problem.
“That's what you have to do. The big difference from the past is that it doesn't cost us confidence when we have to do that. When we are under pressure, we have to defend, then we knew we would get chances.
“We scored the goal and in the second half it was clear Porto came out with high intensity again but they couldn't keep their level until the end.”
Porto were backed by a vociferous home crowd at the Estadio do Dragao.
And Klopp was impressed with the atmosphere while admitting the final scoreline was perhaps harsh on the Portuguese side.
“I don't think it's a result that reflects the two games,” he said. “In the first leg we were the clear better side and dominated the game.
"We made life really difficult for Porto. Tonight it was the other way around, they made our life really difficult.
“It's nice to be part of a game like this when the crowd were behind the team, it was a very good atmosphere and Porto had the power from it. But they needed an early goal and their intensity level dropped a bit and we were still there.”
