Sunderland held on to their first Premier League win since August as Enzo le Fee's penalty helped the hosts sink Chelsea at the Stadium of Light
Le Fee sent Chelsea goalkeeper Mike Penders the wrong way from the spot in the 36th minute. But the awarding of Sunderland's penalty was controversial, with referee Jarred Gillett adjudging Levi Colwill to have pulled Brian Brobbey to the floor - despite both players grappling one another as Brobbey was driving towards goal.
Sunderland's win, just their second in the league this season but sixth in all competitions, will ease pressure on manager Regis le Bris - although his side remain in the Premier League's bottom three. Chelsea, meanwhile, lost their second league match in three and stayed fifth, missing out on a chance to break into the top four.
Sunderland had been booed off by their own supporters at full-time in their last fixture - a 2-0 loss to Dinamo Zagreb in the Europa League. Last week, with pressure mounting, reports say that Frenchman Le Bris would be given more time to turn around his side's form - having led Sunderland to an impressive seventh-placed finish last season.
And the Black Cats produced a fine performance on Sunday, recording their first league win since beating Fulham 1-0 at home in the second game of the season. That said, Le Bris will be concerned about two of his star players - Granit Xhaka and Brobbey - hobbling off with muscle injuries.
Brobbey put in a particularly impressive performance against Chelsea and almost scored early on when he headed Chemsdine Talbi's cross narrowly wide. After Brobbey's substitution in the 77th minute Sunderland switched to a defensive-first approach but were rarely threatened by their opponents. The win meant they climbed from 20th to 18th in the table, one point off safety.