Ferguson was also strongly critical of the visitors' Brazilian for smiling on the ground while he apparently writhed in pain.
Chelsea's victory, secured by Juan Mata's deflected 87th-minute shot, makes them strong favourites to secure Champions League qualification. They can all but secure that with a win over Tottenham Hotspur at Stamford Bridge on Wednesday because of their superior goal difference.
But Ferguson's focus was on the game's late flashpoint, accusing David Luiz of exaggeration, a trait the Manchester United manager said was more common among foreign-born players.
In the moment immediately before Da Silva kicked his compatriot in the back of the leg, David Luiz appeared to elbow the United player. Then, after the defender dropped to the floor following the right-back's challenge at United's corner flag, he could be seen smiling. He then looked around, only to roll back over again with Ashley Cole standing alongside.
This caused Ferguson to believe that David Luiz had been play-acting.
"The ref has been bought by the fact Luiz is rolling about," he said. "But whether the ref will do anything about it, I doubt very much. When a player retaliates he gets punished the most. Luiz rolled about. You see that with these European, foreign and South American players.
"He [Da Silva] retaliates but Luiz quite clearly elbows him twice, then rolls about like a diving swan and that convinces the referee. He was smiling. It's bad. What kind of professional is that? He [Da Silva] was elbowed and he retaliated. That's what always happens, the player who retaliates always gets the bigger penalty and it was clear that Luiz elbowed him twice.
"It was rash what he [Da Silva] did, he's a young lad and should know better but retaliation never works. I wouldn't say it was violent conduct. The referee hasn't even seen it, I don't think he could see it at all. But he has gone with the fact that Luiz has rolled about on the floor and I think that convinced him it was a red card."
Under Football Association rules it appears unlikely that David Luiz will face any retrospective action for his conduct as the episode may deemed to have been seen as soon as Webb issued the red card.
Asked about the incident Rafael Benítez, Chelsea's interim manager, said: "I didn't see the incident or replays. I am always trying to enjoy if we win, you can change nothing if you complain when you lose. I haven't seen it and I will not say too much – there are 200 incidents each weekend in the league."
The victory means Chelsea may need to win only one of their last three matches to secure at least the Champions League play-off spot that comes with fourth place, because of superior goal difference. Benítez said: "It's massive for us. It was an important step forward. For us every game is massive now. We did really well and we have to beat Tottenham and that will not be easy. Tottenham is a good team so it's a big game for both. The managers can talk but the main thing is that the teams talk on the pitch.
"This game was difficult but Wednesday will be even more important. Still it's crucial because [by] winning we will be there but it's even more important to them so it should be a great atmosphere at Stamford Bridge."
With Benítez departing Chelsea in the close season, speculation has linked him to the job of coach at Schalke in the Bundesliga. But the Spaniard stonewalled the issue. "The main thing for me is to concentrate on the next game so I will try to do that," he said, before suggesting that had Chelsea bought more than Demba Ba in January they may have challenged for the title. "In January I was expecting some surprises but they didn't come so we had to carry on."
For Ferguson there was an acceptance that Chelsea were worthy of defeating his side. "The team took their foot off the pedal, [there was] no real edge to our game all day," the Scot said. "Chelsea have deserved to win.
"There's an expectation all the time and we don't approach games in an easy way. Training was fine and there was an edge to it, but today that was missing. It was a bit of a lucky goal, it deflected off Phil Jones so we had bad luck with that. I can't make any excuse for my players in terms of performance. The referee's decisions went against us I thought, they surrounded the referee all day, four and five players all the time and I think that affected the referee."
• This article was amended on 6 May 2013. The original said Ferguson had accused Luiz of acting like a "diving swan".
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