Torres picked up a second booking from referee Mark Clattenburg after going down from a Jonny Evans challenge, with the official deciding that the Blues striker had dived.
The decision reduced Chelsea to nine men after Branislav Ivanovic’s straight red earlier in the match, and the United boss afterwards insisted he has no sympathy for Torres, who he believes could have stayed on his feet.
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“Did he intend to dive? He didn’t choose to go on [running],” he told Sky Sports.
“I think Jonny may have just caught him a little bit, but you can either carry on running, which he could have done, but he chose to go down.
“He could have carried on and scored - that’s what I don’t understand. I would never have missed that chance to go through. I would have taken it anytime.
“I would never have gone down, but he did go down and that’s the issue, and he’s already been booked, so it’s his own fault.”
Sir Alex also admitted Javier Hernandez’s winner was a stroke of luck for the visitors after replays showed the Mexico international was offside when he poked in United’s third goal.
“That’s a bit of luck we got,” he added. “We started the game so well and then just ten minutes or so from half time we lost our way a bit.
“I couldn’t wait for half time, to be honest with you. When they got their second goal after half time, in that moment we had to start performing properly, and I think we did better then.”