Sunderland manager David Moyes insists the controversial decision to send off Sebastian Larsson was a decisive factor in his side slipping closer to relegation from the Premier League after a 3-0 home loss to Manchester United on Sunday.
United already led thanks to a superb Zlatan Ibrahimovic strike before Larsson was dismissed shortly before half-time for a lunge that caught Ander Herrera on the shin.
Sunderland went on to concede a second goal in the first minute of the second half, with Henrikh Mkhitaryan on target, before Ibrahimovic teed up Marcus Rashford to add a third goal in injury-time.
Moyes' men have now failed to score in their last seven Premier League games and they are 10 points from safety with seven games to go, and the former United boss was not happy with Larsson's red card.
"I don't want to blame referees for my position and us losing," Moyes told BBC Sport.
"The result was helped by the referee. Manchester United were playing well but it was a decision that went against us.
"We were hanging in the game and staying in the game and trying to do our best. We gave away a poor goal and I thought we needed to get a lot closer. When we went down to 10 men it made it a lot harder."
Sunderland face West Ham United at the Stadium of Light on Saturday and Moyes insisted he cannot ask for more from his players despite the team having won only one match since December.
"We keep going. We have another home game next Saturday and we have to try and win it," Moyes said.
"We do some good things but just lack a bit of quality but it's not for the want of trying. The boys are doing everything they can.
"The hardest thing as a manager is losing and we're losing a lot. The players care and want to do well and we're not doing as well as we should be."