Harry Redknapp left Old Trafford convinced we would have gained a famous victory but for a controversial penalty that sparked a spectacular comeback from United.
A fine performance in the first half was rewarded by quickfire goals from Darren Bent and Luka Modric - both created down the right flank, where we caused United real problems - and a 2-0 lead at the interval.
United were bound to hit back in the second half and their intentions were clear with the introduction of Carlos Tevez for Nani with the Argentine joining the potent attacking threat of Wayne Rooney, Ronaldo and Dimitar Berbatov.
But they made little impression until the key moment just before the hour.
Michael Carrick burst into the box and was met by a sliding Heurelho Gomes, who clearly palmed the ball away. However, referee Howard Webb pointed to the spot, Ronaldo converted and the rest is history - five goals in a little over 20 minutes and a 5-2 win for the leaders and title favourites.
"It wasn't a penalty and the referee made a terrible mistake," said Harry at Old Trafford. "The players couldn't believe it, they were all saying 'how did he give a penalty for that' but he did and it changed the game.
"I know we conceded four goals after that but the penalty pulled them back into it. They weren't going to win the game from where they were, unless something like that happened.
"In my opinion, it changed the game completely.
"I'm not making excuses for conceding bad goals but at that stage of the game there was no way they were going to get back into the game.
"At half-time I felt confident we were going to score again. Every time we got the ball to Aaron Lennon they were afraid and I felt there were more goals there for us.
"The penalty gave them a massive lift. I felt they were giving the ball away, the crowd was a little edgy and the longer the game went on the more comfortable we were.
"Again, I'm not saying that we should concede the goals we conceded after that but it changed the game for both teams - it gave them a massive lift and I felt we became very deflated over it."