Chelsea looked to have snatched all three points when Jorginho coolly tucked away an 86th-minute penalty after substitute Scott McTominay mindlessly hauled Armando Broja to ground in the area.
But Casemiro earned Manchester United a stoppage-time point at Chelsea as a captivating tactical battle between Erik ten Hag and Graham Potter ended 1-1 at Stamford Bridge.
The Premier League table remains as it was after the draw, with Chelsea remaining fourth after extending their unbeaten start to life under Potter to eight games, and United staying fifth as their unbeaten run in all competitions stretched to six matches.
