Sir Alex Ferguson has demanded a response from his Manchester United players in their "crucial" next game after Saturday's 2-0 defeat at Fulham breathed fresh life into the title race.
United's lead at the top of the table could be reduced to one point by Liverpool on Sunday and Ferguson has conceded his side's stumble - following last weekend's 4-1 humiliation at the hands of the Reds - is coming at precisely the wrong moment.
"As I've said, when you lose games in March and April it can cost you," he told MUTV.
"Fortunately we have a slender lead at the moment but it's not a lot. Obviously I'm hoping we go away for the internationals and come back at our best.
"We've got a home game against Aston Villa in our next game and that's absolutely crucial."
Meanwhile, Ferguson blamed a lethargic start to the game for his side's defeat at Craven Cottage.
Paul Scholes' red card in the 18th minute for a deliberate handball left them with an uphill battle.
Danny Murphy's resulting penalty was then followed up late in the game by Zoltan Gera, before Wayne Rooney was sent off in the closing minutes for an angry reaction to a refereeing decision.
"I was disappointed with the first half, I must admit," admitted Ferguson. "We didn't get started at all and that's cost us the game.
"They were lively and they got stuck in and we expected that. They lost 4-0 to us a few weeks ago so we expected a response from them. We didn't meet that challenge. I think we can thank Edwin van der Sar for keeping us in it.
"In fairness to the team, in the second half they responded to the half-time talking and I think we were unlucky not to get something out of it.
"Their goalkeeper's made some terrific saves but we've missed a few chances ourselves.
"We did really well and we were unlucky. If they'd have got the goal back then they may have even won it.
"In fairness they kept going and good credit to them for that."