Wilfried Zaha returned to inspire Crystal Palace as the Eagles recorded its first goals and points of the season en route to consigning Chelsea to back-to-back Premier League defeats.
Flying winger Zaha injured his right knee during the opening-day defeat to Huddersfield Town and has been powerless as Palace lost its opening seven league matches without scoring a goal.
Another defeat to nil would have set an unwanted English league record at nine, including one at the end of last season, but Selhurst Park erupted early on when an Andros Townsend cross crept past Thibaut Courtois via a combination of Yohan Cabaye and Cesar Azpilicueta.
Tiemoue Bakayoko was given the freedom of the Palace area to head home his first Premier League goal and level the scores, but the influential Zaha – who was a menace throughout – restored Palace's lead shortly before the break with a cool finish.
An inevitable second-half barrage arrived from Chelsea and Cesc Fabregas lashed an effort against the crossbar, but Palace clung on for a priceless victory.
It marks another disappointment for Antonio Conte, whose side was beaten 1-0 at home by Manchester City last time out and the Blues now trails Pep Guardiola's league leader by nine points.
Palace remains bottom of the table, seven points adrift of 17th, but the return of Zaha will give Roy Hodgson – who tasted victory as Palace boss for the first time – renewed optimism.
Zaha provided Palace with fresh attacking impetus and he forced Courtois into an early save after collecting Townsend's low left-wing cross and turning Gary Cahill in the area.
The wait for a goal was over in the 11th minute. James McArthur cleverly slipped a pass to Townsend, whose drilled cross ricocheted off Cabaye's knee under a challenge from David Luiz and clipped Azpilicueta before squirming past Courtois.
Palace's frailties were exposed with startling ease just seven minutes later, though, as Cesc Fabregas fired in a corner from the right that Bakayoko headed in unmarked for his first Premier League goal.
Zaha lashed an effort past the left post, while more poor marking at a corner led to Michy Batshuayi – deputising for the injured Alvaro Morata in one of four Chelsea changes – heading wastefully over the crossbar.
Chelsea then lost Victor Moses to a hamstring injury before its misery increased on the stroke of half-time.
- Asian Games 2023: Overall medals tally, October 2 - LIVE - Ayhika-Sutirtha pair wins bronze in women’s doubles table tennis; India stays fourth with 56 medals
- India vs Bangladesh hockey LIVE Score, Asian Games 2023 updates: Harmanpreet scores hat-trick IND leads 8-0 vs BAN after third quarter
- New Zealand vs South Africa LIVE SCORE, World Cup 2023 warm-up: NZ 24/1 vs SA; Ngidi gets Young
- Asian Games 2023 LIVE updates, Hangzhou 2022 medals tally: Satwik-Chirag, Kidambi Srikanth win; Indians pick three medals on October 2
- Kabaddi Live Score, Asian Games 2023: India leads Chinese Taipei in Women’s Group A, Streaming info and updates