Rafael Benitez has revealed that it was only on the team coach going to Anfield that he decided to use Spanish striker Fernando Torres from the start against Manchester United.
The under pressure Liverpool boss waited until the last moment before deciding Torres, who was struggling with a groin injury, could cope with a battle against the Barclays Premier League champions that could make or break his side's season.
After the 2-0 win, Benitez said: "In the morning I had decided that he would be involved, but I needed convincing he could start rather than just be a substitute.
"I talked with Fernando on the coach, and that was when I was really convinced that he could play.
"Playing Fernando was a difficult decision. He was not training, the same as Steven Gerrard.
"But after talking with him we decided it was better to start the game with him."
Defeat would have meant Liverpool's worst run since 1953, when they were relegated from the top flight.
But Torres ensured a first win from five attempts by firing the opener in the victory.
Substitute David Ngog added a second in stoppage time after Nemanja Vidic and Javier Mascherano had both been sent off in a fierce confrontation between English football's bitterest rivals.
Benitez decided it was better to begin the match with Torres short of fitness, rather than try to cope without him.
"You could see he was not 100% fit, but sometimes 80% of Fernando can make a difference," added the manager.
"We had to be very careful with him, that is why we took him off near the end.
"You have to take care of him. But we were waiting for that final pass and when it came we knew he would score."
Liverpool had been subjected to brutal criticism before the game following four successive losses, their worst run in 22 years.
And Benitez was relieved as the run was ended against the champions.
"I am very pleased for the club, the players and all the staff," he said.
"We needed to change our luck with a win, and this was a fantastic win.
"Beforehand we were talking that this was the perfect game to change our luck, against a good team.
"We needed to perform in front of our fans, and to show what we were capable of. It was a fantastic performance from our players."
The moment Torres got away from Rio Ferdinand to fire in the opener in the 65th minute was the key, said Benitez, who believes his Reds side were deserved winners.
"Small details against such good opposition can be the difference," he added.
"They had some early chances, but we were on top of them from the beginning.
"But when Fernando scored the goal, that made the difference. The team wanted to win, to show what they could do. And with every last one of our fans behind us right to the end, we managed it."
Benitez denied it was risky to utilise his talismanic striker from the beginning.
He said: "Fernando had just two light training sessions ahead of the game. We could not push him too hard, he was working with the fitness coach to be sure he was not a risk.
"But we knew he was not 100%, but he was not a risk. In the end we decided to use him."
With four Premier League defeats already this term - two more than in the whole of last season - Liverpool needed to win to keep their title hopes alive.
And Benitez hopes the result can be the catalyst for the remainder of the campaign after confounding their critics.
He added: "We needed to win for our confidence, and it will be a big boost for the team because the win was against such a good team.
"The fans are elated, and all the players are in the same mood. You have to be positive in football, you have to be ready.
"Our players are good players. People talked before the game that we were not, but I know that is wrong. We have many players injured, that is the problem.
"When they are fit we can be a problem for anyone. And the rest of the team will support them.
"For me the difference is that the team was working so hard to help the strikers.
"Hopefully that win will now kick-start our season. I am sure we have a team good enough to win many games in a row.
"The players just did not want to lose. They wanted to win, to show character, and this was the perfect response from them."