Having seen the replays, I think we'd have been lucky to get a penalty on either of those. It did appear Silva clipped his own heel, he might not have realised it himself at the time judging by his reaction. Sergio's would have been a soft one, wasn't much of a pull and the clip on his heel was hard to spot, it was the combination of the two which did him, just unlucky really.
Regardless of that when you hit the woodwork 3 times and concede with a handball you still have every right to claim you were unfortunate. The game was littered with bad decisions by the ref and his linesmen too which affected the flow of he game throughout.