Sunderland won an "enormous, enormous" three points as they overcame fellow relegation strugglers Swansea, according to manager Sam Allardyce.
The 4-2 victory against 10 men moved the Black Cats to within a point of the Welsh side, who are 17th in the table.
"For us it's an unbelievable win, to give us encouragement and hope going forward," said Allardyce, 61.
Allardyce said his side, who have back-to-back league wins, took advantage of controversial refereeing decisions.
Relive Sunderland's victory at the Liberty Stadium.
Sunderland banked on a hat-trick from Jermain Defoe, but his first and third goals appeared to be from offside positions and arrived either side of Swansea right-back Kyle Naughton being harshly sent off.
"We manipulated or played with the situation as it panned out," added Allardyce after his 450th Premier League game as a manager. "That's all we can do. We have taken the opportunity rightly or wrongly to win the game.
"He only stepped in because the referee who was supposed to referee the game was ill. In his defence before the game he pointed out how big this game is. But things happen under pressure and when people are under pressure they make mistakes."
Only Sir Alex Ferguson, Arsene Wenger, Harry Redknapp and David Moyes have now taken charge of more Premier League games than Allardyce.
The ex-Bolton boss used all his experience to change his side's tactics at half-time as, despite facing 10-men, he believed Swansea's 2-1 lead at the interval put "enormous pressure" on the visitors.
"That made us do a high press which we don't normally do away from home," added Allardyce," who guided Sunderland to their first league win at Swansea since 1963.
"That's what worked for us in the end and clinical Mr Defoe has won us the game. We are putting the myth he can't play up front on his own to bed.
"Irrespective of whether you're in a dominant position or not, he can change a game in your favour by giving him one chance."
Defoe's fourth Premier League hat-trick took his tally to five goals in two games and 12 in all competitions this season.
The 33-year-old - who described the win as "massive" - has scored crucial goals of late and found the net with all of his shots at the Liberty.
"On a personal note to score a hat-trick, especially such an important one is great," said the former England striker.