Sam Allardyce felt Sunderland were denied what he saw as a "blatantly obvious" penalty by referee Mike Dean in their 0-0 home draw against Arsenal on Sunday.
Sunderland moved above Norwich City and out of the Premier League's bottom three on goal difference after the battling point against Arsene Wenger's side at the Stadium of Light.
But Allardyce was frustrated that striker Jermain Defoe was denied a first-half penalty when his shot struck the arm of Arsenal defender Per Mertesacker from close range.
"It is not as if we haven't created chances - Patrick van Aanholt hit the post and the referee should have given us a penalty," Allardyce said at his post-match news conference.
"It was blatantly obvious for me, [Mertesacker] turns his back, sticks his arms out. When you are trying to block a shot you are not supposed to turn your back.
"[He was] not looking at the ball, stuck his arms out, stops a certain goal. For me - definitely, 100 per cent a penalty.
"If we had got it that is not saying we would have scored or won it on that - Arsenal could have come back - but we would have liked it."
Allardyce thought Sunderland may have deserved to win the game on the strength of their second-half performance, but was thrilled to see his team move outside of the dreaded drop-zone with only four matches left to play.
"I'm slightly disappointed we haven't taken all three on the overall performance," he said.
"At the start of the game or at half time if you had said 'will you be happy with a point?' I would have said yes. But at the end of it after our slight change in tactics that allowed us to get into the game more in the second half, with the chances we created, I am slightly disappointed we didn't get that goal to pinch it, which would have been huge for us.
"But it is another clean sheet and a very, very good point. Of course for the first time for many, many months it moves us out of the bottom three, albeit on goal difference.
"Psychologically that will hopefully be a big boost for the players. Our destiny is in our own hands with four games to go so we will see whether we can maintain this level of performance and produce it at Stoke City next week.
"I am really pleased with the level of performance with the pressure we were under."
