MARTIN Laursen says Villa will not give up on their European quest and has called for his team-mates to prove they are "men and not boys".
Villa were given a flicker of hope by Fulham's defeat of Everton yesterday but still trail David Moyes' side by seven points with eight games to go.
They are also a point behind Portsmouth in the race for the InterToto with Pompey, who beat Villa 2-0 at the weekend, facing a relatively easier run-in.
Laursen insists the home clash with Sunderland is now a must-win game.
"This is a test for us now,'' he said. "But that's what it's all about. We have to prove we are men and not boys.
"We have to prove we can stand tough when things are not going our way.
"When you are winning, everything is easy. When you have a few bad results you have to show your character and that is what we will do. We are not giving up.
"We have a great opportunity against Sunderland to bounce back. Sunderland are fighting for every point, but so are we.
"This is a great challenge. We have to forget about the Portsmouth result and try to learn from our mistakes. We have to think only about Sunderland now."
Laursen believes Villa paid the price for missed chances at Pompey.
"It was a tough one to take because I still thought in the second half we were in the game,'' he said. "I felt we had some chances and we could have scored.
"They didn't have that much, so it was frustrating to have conceded the two goals in the first half - especially the second. But we have to move on.''
Villa gifted Jermain Defoe his opener and were the victims of a bizarre own goal for the second, which gave them a mountain to climb. "It was one of those days where we were unlucky,'' said Laursen.
"We know we didn't play well and could have done better, but there were some frustrating things as well.
"With the second goal, if Scott (Carson) cleared the ball 100 times more, he would probably not hit Nigel (Reo-Coker) in that way for an own goal.
"We played some decent stuff, but you can't really be happy about anything after a 2-0 defeat."
Laursen backed Olof Mellberg after his first sending-off for the club.
"I don't think what Olof did was enough for the second yellow card."