It was no more than Palace deserved, and while Chelsea continued to enjoy as much as 79 percent of the possession at one point in the first-half, Palace restricted them to just one chance: Gallagher dragged wide from Noni Madueke’s slipped pass.
Sadly, Chelsea would improve after the break – and following a lengthy delay due to a technical difficulty with the officials’ equipment, the visitors duly scored with their first shot on target.
Racing forwards from right-back, Gusto’s pull-back found Gallagher on the penalty spot, and the midfielder crashed home a half-volley.
The goal gave Chelsea confidence and, mere moments later, Thiago Silva’s near-post header appeared to be goalbound before Mateta intervened. Then, Cole Palmer cut inside and hit a rasping shot into the side-netting.
Yet Palace weathered that storm and enjoyed the better chances of the next spell in the game, França combining well with Mateta and playing an intricate slide-rule pass with led to the forward having a shot blocked on the slide by the lunging Silva.
After a bright opening to the second-half, the next 10 minutes were rather more cagey, but Chris Richards made a succession of headed clearances and Muñoz did well to get his own head on a fierce Caicedo cross; from the edge of the box, Ben Chilwell fired a rasping drive not far over.
As the half wore on, Wharton’s influence on proceedings grew, the 20-year-old showcasing his impressive ability to break the lines with a well-placed pass. On 75 minutes, one such pass found França 30 yards from goal, and his firm effort forced Petrovic to beat the ball away with both hands.
The match was there to be shaped by such fine margins and, seconds after substitute Odsonne Edouard had almost found Mateta with a through ball, his weaving run and dragged shot was just a Levi Colwill interception away from doing the same yards from goal.
As the game ticked into injury time, heartbreak for Palace – and from a familiar source, too, as a Palmer pull-back picked out Gallagher on the edge of the box, and he swept home a low winner into the far bottom corner.
Undeserved gloss was added to the scoreline deep into injury time when Palmer led another counter-attack, finding Enzo Fernandez who checked inside and found the top corner.
Palace: Henderson (GK), Muñoz, Richards, Andersen, Mitchell, Wharton, Lerma, Hughes (Ahamada, 78), França (Edouard, 84), Ayew, Mateta.
Subs: Johnstone (GK), Ward, Tomkins, Clyne, Riedewald, Ozoh, Schlupp.
Chelsea: Petrovic (GK), Gusto (Gilchrist, 84), Disasi, Silva (Colwill, 61), Chilwell, Fernandez, Caicedo, Gallagher, Palmer, Madueke (Nkunku, 45), Jackson (Sterling, 79).
Subs: Bergstrom (GK), Chalobah, Chukwuemeka, Casadei, Mudryk.
As It Happened
Sophie Anderson, a UK-based writer, is your guide to the latest trends, viral sensations, and internet phenomena. With a finger on the pulse of digital culture, she explores what’s trending across social media and pop culture, keeping readers in the know about the latest online sensations.