Rafa Benitez couldn't hide his frustration after a harsh penalty decision turned the game in Manchester United's favour at Old Trafford.
Liverpool were leading 1-0 after a superb headed goal from Fernando Torres but United hit back when Antonio Valencia went to ground in the penalty area after a challenge seemingly outside the box from Javier Mascherano.
Despite seeing his first effort saved, Wayne Rooney fired home the rebound and they took the three points when Ji-Sung Park made it 2-1 on the hour mark.
Torres almost claimed a point for the Reds in the closing stages but he mis-kicked when presented with a clear opening.
"It was a tight game and very close and we had a really good chance at the end for Fernando and Yossi," Benitez told his post-match press conference.
"We are disappointed. We didn't create too many chances but I felt we were always dangerous and in these games small details can make a big difference.
"We made a great start and Fernando scored a very good goal but I felt we conceded too early. The penalty was the turning point for them and it made a big difference.
"We were playing well and we had confidence and one situation changed everything. We are disappointed but you cannot change these things. Sometimes they go your way but this season more than we expected things have gone against us.
"From the bench I asked the TV people who told me the challenge was inside the box so it was a penalty. Watching the replay myself there is a lot of doubt in my mind. It's not clear as there was some contact outside the box but it was disappointing."
Benitez was also quizzed about Torres losing his temper during the first half when he was shown a yellow card.
The boss added: "We were talking at half-time with him. It's not easy when you are a player on the pitch fighting, and decisions you don't understand happen. He was focused again in the second half and he was okay."
Asked where this result leaves Liverpool's chances of a top-four finish, Benitez said: "We have to keep going. It depends on the other teams if they lose some games but we have to be focused now on the next one.
"We have to get three points against Sunderland and then we will see. If we can win our remaining games we will be there fighting until the end.
"As a manager you have to believe. Now it will be more difficult but we have to keep pushing and have the belief we can do it."
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