It was the biggest game of the season, the Premier League decider. If Chelsea won, they would have drawn level with United on points, with a superior goal difference to boot.
The last time that United lost at Old Trafford was against Ancelotti's men. The last time that they conceded a headed goal at Old Trafford was to Fernando Torres.
All the signs pointed to a Chelsea victory.
But 36 seconds in, Ji Sung Park broke from midfield and fed Hernandez for the opener. It was a killer blow for Chelsea, who had clearly been told to avoid conceding early at any costs.
The resulting spat between Carlo Ancelotti and David Luiz, who Carlo blamed for the goal, saw Alex start to warm up after four minutes had been played.
While Chelsea struggled to maintain possession or create chances, Manchester United were finally playing like champions with Hernandez missing another chance and Rooney testing Cech from distance.
A tough tackle from Ivanovic on Rooney saw the Serbian booked and the United fans were clamoring for a sending off when the right back committed another foul on United's main man up front.
Antonio Valencia, preferred to Nani, was giving Ashley Cole a torrid time whilst Ryan Giggs was pulling the strings in the center of midfield, where Mikel and Essien were struggling for a foothold.
It was the 37-year-old Welshman that skinned Kalou and set up Vidic for United's second goal, seemingly the beginning of the end for Chelsea.
Drogba went close with a couple of free kicks towards the end of the half, but for the most part, Chelsea's attack was not functioning as Kalou and Malouda seemed afraid to run with the ball.
In the second half, Alex was brought on for Luiz while Ramires replaced Mikel, sparking an immediate difference as Ramires showed a willingness to run with the ball, using his pace to test United.
However, it meant that only one of Anelka or Torres could be introduced and Ancelotti would have risked Abramovich's wrath by not bringing on the £50 million man.
Kalou was withdrawn but El Nino failed to make an impact, dragging one shot wide of goal.
Chelsea were able to pull back a consolation through Lampard but never looked like equalizing. In fact, Man United were doing all the attacking and Rooney could have netted a second half hat-trick were he not thwarted by Alex.
Manchester United deserved to win the match and the championship, and it is clear that there are issues at Chelsea that need to be resolved.