Sir Alex Ferguson warned Manchester United's Premier League rivals that his side's 2-0 defeat at Liverpool will only strengthen their determination to retain the title.
United cut a strangely subdued look as second half goals from Fernando Torres and David Ngog at Anfield on Sunday condemned the champions to their first defeat in 12 matches.
Ferguson was forced to admit United had been out-played and out-fought. But the United manager believes the frustration of a result which allowed Chelsea to move two points ahead of them at the top of the table is certain to prove the catalyst for a powerful winning run.
While any defeat against the team United hate the most will always stick in Ferguson's throat, the Scot knows his side were beaten twice by Rafa Benitez's men last season and still ended the campaign as champions.
They bounced back from a 4-1 defeat to the Reds at Old Trafford in March by surging to the finish line in the title race and Ferguson expects more of the same this time.
"We will always react. That is the important thing about our club," Ferguson said.
"They have always had to do that. It is not something unusual for us. At some points of your season you are going to have disappointments.
"Last year we lost 4-1 at home to Liverpool, got hold of the bit again and went on to win the league and that is our challenge."
After four successive defeats, Liverpool knew another loss would end their title hopes, so it was no surprise that Javier Mascherano, Fabio Aurelio and Lucas snapped into tackles with abandon.
But United midfielders Michael Carrick and Paul Scholes were overwhelmed and Ferguson conceded they offered little in the way of a response to the physical challenge.
Torres opened the scoring in the 65th minute when he got clear of Rio Ferdinand and lashed home a sublime finish.
A bad day for United got even worse when Serbian defender Nemanja Vidic, already on a booking, was dismissed for a clear professional foul on Dirk Kuyt - his third successive red card against Liverpool.
David Ngog added Liverpool's second goal in stoppage time and Gary Neville, an unused substitute, appeared to exchange words with home fans near the dug-out as United's frustration boiled over.
"All in all Liverpool were the better team and created more chances," Ferguson said. "They deserved their victory. We created few chances. We have let ourselves down with our penetration.
"I think we got caught up in the atmosphere and the wounded animal aspect of it.
"Their fans were fanatical and every decision they put the referee under pressure all the time."
Ferguson felt referee Andre Marriner had been unable to cope with the red-hot atmosphere and slammed the official for failing to award a first half penalty for Jamie Carragher's foul on Michael Carrick.
Marriner, who did sent off Reds midfielder Javier Mascherano in stoppage time, also only showed a yellow card to Carragher when, with the score still just 1-0, he hauled down Michael Owen as the former Liverpool striker threatened an equaliser.
"I felt Carrick in the first half was a penalty and of course the controversial one that everyone will be talking about was when Carragher brought Michael Owen down on the edge of the box," Ferguson said.
"He is their most experienced and best defender and if he goes off at that stage it would have difficult for them.
"When Vidic got his first booking he committed a foul but won the second ball and that's what the referee booked him for. The crowd got him booked.
"On the second booking, I don't think it was a vicious foul, it was obstruction more than anything. The fact he has been booked puts the referee under pressure.
"That atmosphere is hard to handle for the referee. Whether he had enough experience I don't know but he will certainly learn from it."