Manchester United inched closer to the Premier League title after a 2-2 draw with West Ham, but the manager was unhappy that the striker's challenge on the keeper went unpunished
The league leaders were twice trailing by a goal to 11th place West Ham, but Robin Van-Persie's 77th minute equaliser secured a point for the Red Devils. The draw takes United to 81 points, 13 clear of rivals Manchester City with five games remaining.
Though his team fought back into the game to secure the draw, Sir Alex was clearly unhappy with Carroll's challenge on De Gea at a corner as he steamed in and collided head-on with the Spaniard, and the referee's failure to punish the striker.
When asked about the challenge, Sir Alex told Sky Sports: "I think it's obvious. I don't think we need dwell on that, it's an obvious red card but the referee has seen different.
"[West Ham] are very aggressive as we've seen tonight. You hope there's a strong referee... I'm not so sure we got that tonight."
However, the 71-year-old did draw some positives from the game, saying they played "like champions", after battling back from a goal down twice on the night.
"We had to stand up to a lot there, but they kept going, our players," he added. "We were down twice, came back and played like champions I thought.
"Magnificent in terms of determination and courage to play, so I was pleased with the result."