Sunderland beat Chelsea 3-2 n a thrilling Premier League clash on Saturday coming from behind twice.
The win left the Black Cats fourth from bottom with 35 points from 36 matches, one point ahead of bitter north-east rivals Newcastle United who have played a game more and were held to a disappointing 0-0 draw at already-relegated Aston Villa.
Sunderland can secure top-flight football next season by beating visiting Everton on Wednesday.
The home side had the upper hand in the first half but were skating on thin ice after Diego Costa's fine finish from a tight angle and a Nemanja Matic goal either side of Wahbi Khazri's stunning volley gave Chelsea a 2-1 lead.
Sunderland turned the match on its head after the break with the home faithful roaring them on at the Stadium of Light.
Fabio Borini equalised in the 67th minute after Chelsea skipper John Terry deflected his stinging low shot from the edge of the penalty box and keeper Thibaut Courtois could not keep it out despite getting a hand on it.
Defoe then sent the fans into raptures after more sloppy defending by Chelsea as a clumsy John Obi Mikel clearance gave the striker time and space to unleash an unstoppable shot into the bottom right corner.