In the 77th minute of a feisty encounter at Upton Park, Robin van Persie equalised from close range to leave the Reds needing a maximum of six points from the remaining five games to clinch a 20th English league crown.
Antonio Valencia had earlier cancelled out Ricardo Vaz Te’s header with his first goal of the season but the home side were up for the fight and retook the lead early in the second half through Mohamed Diame’s wonderful strike.
“We had to stand up to a lot but our players kept going,” Sir Alex said. “We were behind twice but we came back and I thought we played like champions.
“We were magnificent in terms of our determination and courage to play. We don’t like losing and we showed that again tonight so I was pleased with the result.
“It’s a game closer to the title. We have five left – three at home, two away – and the players are showing they want to win it. There’s no doubt about that. We’ve got a nice cushion with our lead but we don’t want to make any mistakes."
After van Persie’s leveller, United poured forward in search of a winner but found Jussi Jaaskelainen in inspired form in the Hammers goal.
“We were the team that was going to win it," Sir Alex said. "I think their goalkeeper saved them in the last 20 minutes. He made great saves from Robin and Chicharito, and Wayne Rooney had a shot cleared off the line.