Despite heading into the game having lost just once in their campaign, Chelsea arrived at Highbury on December 12, 2004 needing to silence a few of their doubters against an Arsenal side hoping to retain the title they had won during their 'Invincibles' season.
The supporters packed into Arsenal's famous old ground were treated to an enthralling match between two sides desperately looking to pick up a crucial win before the hectic Christmas schedule.
A dramatic afternoon started with a stunning strike in the second minute, and it came as no surprise to anyone to see Thierry Henry break the deadlock.
The Frenchman climbed to head a long pass back to Antonio Reyes, before quickly receiving the ball back. Henry took one touch, and struck a volley on the turn to give Petr Cech no chance of keeping the ball out.
Many critics may have expected this impressive Chelsea side to crumble after such an early setback, but they responded superbly to get back on level terms 15 minutes later.
Eidur Gudjohnsen then went close on two occasions, with Almunia making a good save to keep out the second shot after the Iceland international had miscued his earlier effort.
What happened in the 29th minute was Henry at his best. Football fans had seen the Gunners legend do it before, but it was still a surprise to Chelsea as he took a 25-yard free kick quickly to catch the wall and Cech off guard.
Drogba's presence in the box caused problems in the first minute of the second half, and Chelsea capitalised as William Gallas headed a Lampard cross into the path of Gudjohnsen, who slotted home to equalise for the visitors.
Played at a slower pace, the pattern of the second half appeared to suit Chelsea, but they missed a great chance to take the lead when an unmarked Lampard headed wide at the back post.
Arjen Robben threatened to steal the show with a clever run through the heart of the home defence, and the frustration was clear for the Dutchman when he ended the move by seeing Almunia save his weak effort.
After spending an extended spell on the back foot, Arsenal looked the more likely of the two sides to find a winner in the closing stages.
Perhaps the biggest surprise of the afternoon came when Henry missed the opportunity to secure the victory as he fired a shot over the crossbar from a good position inside the box.
The first of many battles between Mourinho and Arsene Wenger would end in a 2-2 draw, but it was Chelsea who were celebrating at the end of the season as they stormed away with the title.
Over the course of the campaign, plenty of victories caught the eye, but it may have been the battling draw at Highbury which convinced the doubters that this Chelsea side were ready to be champions.
Arsenal: Almunia, Lauren, Toure, Campbell, Cole, Pires, Flamini, Fabregas, Reyes (Clichy), Bergkamp (Van Persie), Henry
Chelsea: Cech, Ferreira, Carvalho (Drogba), Terry, Gallas, Duff, Tiago (Bridge), Makelele, Lampard, Robben, Gudjohnsen (Parker)