"At this moment, we are the unluckiest team in the Premier League - it's the reality", Mourinho told Sky Sports News afterwards.
United were held to a 1-1 home draw by Arsenal on Saturday, after a late header from opposition striker Olivier Giroud, meaning that Juan Mata's strike was cancelled out.
Mourinho was keen to stress how United were unlucky not to claim all three points and continued: "Of course it is two points dropped".
Walcott continued: "I would say we'd want more from our first half performance - but it could be a fair result to get a point".
The great escape for the Gunners meant that, even though they were unable to take their chance to go to the top of the table, they retained their six-point advantage over United.
Wenger praised Arsenal's "never-give-up attitude", but he could not explain why it took them until the 89th minute to threaten David de Gea's goal.
Mourinho's comments and being benched for such a crucial game despite being fit are not likely to do Rooney's confidence any good.
Have we ever had such a strong squad of players to choose from?
"De Gea was on holidays, when [Petr] Cech made two or three very good saves or when you miss two or three very good chances and you are in total control then the concede late, then the feeling is like a defeat".
The draw left Arsenal fourth on 25 points, the same as Chelsea. Mourinho, who shared an icy handshake with Wenger before and after the match, must now rouse his players for Thursday's key Europa League home game with Feyenoord.
While Liverpool's progress was checked by a goalless draw at Southampton, City clambered back level with the Anfield club on 27 points from 12 matches thanks to the double from old favourite Toure whose stand-off with Guardiola was quickly forgiven and forgotten.
"They have always been brilliant with me, always supportive". This was the game that United had to win and for long periods of the second half it looked like they would.
"I felt from the very start - whether it was a game-plan to sit in and see what United had to offer - but a 0-0 or 1-1, any draw in fact, and Arsenal were going to be happy with that. The league this year is so hard, and you can't call it, but in years gone by we haven't got anything from this game".