Ten-man Chelsea fought to the end but their flickering title challenge was finally snuffed out at the Emirates Stadium to spark a Premiership party at Manchester United.
On and on the visitors pushed looking for salvation. In the end, there was none, effectively allowing Arsene Wenger to gift-wrap domestic supremacy and send it north to old rival Sir Alex Ferguson.
• Wenger - United didn't need our help
Mourinho can be justifiably proud of his side for their fighting spirit but in excusing Didier Drogba, Ashley Cole and Ricardo Carvalho from duty because of the injuries they have carried through an exhausting schedule, the Chelsea coach probably knew what was coming.
All that remains now for Mourinho is the delicate decision over whether to reciprocate the guard of honour Ferguson offered his champion side two years ago when United head to Stamford Bridge on Wednesday, and the small matter of an FA Cup Final meeting with the Red Devils on May 19.
Mourinho could cite an injury problem for all his absent stars but for all the world, it appeared as though the Chelsea boss had given up the title ghost.
With Drogba and Andriy Shevchenko both missing, Shaun Wright-Phillips became probably the smallest attacking line-leader in Premiership history.
Wright-Phillips represented a clear threat to the Arsenal defence, as did Joe Cole, but with Frank Lampard delivering a succession of set-pieces straight to Jens Lehmann, the home goal was relatively quiet.
Cole did provide the one genuine moment of excitement, when he reacted quickly amid some defensive hesitancy from Arsenal to cut the ball across the six-yard area. Sadly for Chelsea, there was no-one in a blue shirt with the necessary thirst for goals to get on the end of it.
It would be hard to imagine Wenger sending out his team with the specific task of doing United a favour but clearly that was the by-product of their own desire to emphasise their effectiveness against their London rivals.
Indeed, having completed a league double over Ferguson's men this term, Wenger might wonder why his team have ended up so far off the pace.
The answer lies in a lack of consistency in front of goal which was evident again as Emmanuel Adebayor wasted two gilt-edged opportunities to put the Gunners in front.
Adebayor's first chance came after a delightful exchange of passes between Abou Diaby and Cesc Fabregas. The ball eventually arrived at the feet of Denilson, whose flick into the path of Adebayor was inspired. The finish was anything but as the Togo forward fired straight at Petr Cech.
At least that effort was on target. The second, when Emmanuel Eboue chipped a long ball deep into Chelsea territory, flew harmlessly wide of the visitors goal.
The method of creating the opportunity should have served as a warning to Chelsea, and in particular Boulahrouz.
But, when Lehmann launched a punt forward that John Terry failed to cut out, the Dutchman was caught out by Julio Baptista's pace.
In his desperation to challenge for possession, Boulahrouz succeeded only in bundling the Arsenal man over. The penalty award was automatic, as was the red card and Gilberto stepped up to calmly send Cech the wrong way.
Furious Chelsea assistant-boss Steve Clarke berated referee Alan Wiley all the way to the tunnel after the half-time whistle had gone.
Maybe it was the sheer frustration of feeling the title slip from their grasp that provoked Clarke. There was little else to trigger such a feeling of injustice as TV replays proved Wiley had got the decision exactly right.
While not particularly spiteful, there was an undercurrent of physicality running through the contest which meant it was no great surprise when Denilson was carried off 10 minutes into the second-half, the legacy of a thunderous challenge from Paulo Ferreira.
Against his former club, William Gallas should have doubled Arsenal's lead instead of heading Fabregas' corner over from five yards.
Had Gallas found the net, it would have saved Ferguson and his players 20 nervous minutes after action-man Michael Essien had levelled with a glancing header as he met Wright-Phillips' low cross at the near post.
Twice Lehmann required the end of his fingers to deny Chelsea after Cole's superb finish had correctly been ruled out for offside.
But no matter how many bodies the visitors pushed forward, a winner proved elusive allowing Ferguson to be thankful to Arsenal - for possibly the first time in his life.
• Wenger - United didn't need our help
Arsene Wenger is not expecting to receive a bottle of red wine from Sir Alex Ferguson as thanks for handing Manchester United the Premiership title - but the Arsenal boss believes the Red Devils have deserved their triumph just the same.
The Gunners' home draw with Chelsea at the Emirates Stadium means United now have an unassailable seven-point advantage at the top of the table.
And, while his own side out of the running many months ago, Wenger admitted United were worthy champions.
'The table doesn't lie,' he said.
'Manchester United have scored more goals than anyone else and you can only say they deserve the title.
'No, I don't expect to receive a bottle of wine from Sir Alex Ferguson but congratulations to him anyway.
'They have been the most consistent side and they also have individual players who can make a difference.
'Chelsea and Manchester United were both strong sides but there were a few turning points when United didn't show any weakness and they had an offensive ability the others did not have.'
The frustration for Wenger is that Arsenal completed a Premiership double over United this season.
In fact, the Gunners only lost once against their fellow members of England's so-called `big four', defeats against the likes of Sheffield United and Manchester City ultimately letting them down.
'It is a big frustration,' he said.
'What I have to get right in the summer is to evaluate what we need but there are signs that when everybody is fit we have a good chance.
'You could sometimes say we over-complicated things in our finishing this season and we have to consider that we are 20 points behind Manchester United.'
With a place in next season's Champions League qualifiers secure, Wenger is already planning for the new campaign.
His most immediate priority is to discuss the future of Jose Antonio Reyes, who has spent the season on loan at Real Madrid.
'I will sit down with Madrid and talk about Reyes this week,' confirmed Wenger.
'Once we find out what they want to do with him we will make a decision.
'We have missed him at some points this season because he is a natural winger but we shall wait and see what happens.'
