The midfielder was a standout performer in San Sebastian until referee Nicola Rizzoli dismissed him for a second bookable offence in added time.
"I thought we defended well as a team, we pressed them in the middle of the park and got up against them," Ferdinand told MUTV. "Felli won a lot of balls in midfield and was maybe a little bit unfortunate with the sending off. I think he only made three or four tackles in the whole game but that is what happens in Europe sometimes.
"There's a little bit of frustration. When you get a penalty, you expect to score. We had a couple of half-chances with Chicharito getting across the post once and Robin (van Persie) hit the post once as well. But, it's important to keep a clean sheet away in Europe and hopefully steal a goal here or there. It was just unfortunate that we didn't get the rub of the green."
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