Paolo Di Canio apologised to Sunderland fans after admitting Aston Villa showed more fight in their
6-1 victory over the 10-man Black Cats at Villa Park.
Christian Benteke scored a hat-trick as Villa equalled Sunderland's 37 points - five more than 18th-placed Wigan.
"We have to apologise to our club, the fans - they travel and it is not fair," said Black Cats boss Di Canio.
Sunderland's PL run-in
4 May: Stoke (h)
12 May: Southampton (h)
19 May: Tottenham (a)
"Aston Villa looked like Sunderland did in the last two games - there was a fire, ferocity in their intention."
The visitors, who had won their previous two matches, could have moved eight points clear of the Premier League's bottom three with victory, but they capitulated against a free-flowing Villa side.
Captain Ron Vlaar, with his first goal for the club, gave Paul Lambert's side the lead but Danny Rose equalised within a minute.
Andreas Weimann put Villa in front seven minutes before half-time, Benteke scored a second-half treble and Gabriel Agbonlahor scored a late sixth.
The Wearsiders, who remain above Villa and Newcastle solely on goal difference, finished the game with 10 men after Stephane Sessegnon was given a straight red card in the 70th minute for a challenge on Yacouba Sylla.
"Every time we can lose, but not in this manner," said the Italian, whose side face Stoke, Southampton and Tottenham in their final three matches of the season.
"Aston Villa, a team with real desire. They played like it was the last chance of their lives.
Monday night blues
Sunderland haven't won any of their last 17 Premier League games on a Monday, a run stretching back to April 2002 when they beat Leicester 2-1. Sunderland's next game? At home to Stoke next Monday.
"We thought the main job was done. It is obvious if the team perform in this way. The first responsibility is with the manager and then the players.
"This is a medicine that can let us understand that we have to play with desire and commitment, otherwise we have a defeat. This is a humiliation that can help.
"It is not acceptable tonight - maybe we were fooled by two wins in a row and now we have to make sure we get points against Stoke at home."
Benin international Sessegnon, 28, could miss the final three games of the season following his straight red card, but Di Canio says the club plan to appeal his dismissal.
"We saw the clip, there is not a bad challenge," he said. "With the dynamic of the challenge, it can be a trap for the referee because from distance you see the dynamic, but there is not a nasty challenge."