Pulisic took advantage of confusion in the City backline to steal the ball in the Chelsea half, race away on a counterattack and calmly curl the ball past City keeper Ederson.
After Kevin De Bruyne equalized with a free kick and Raheem Sterling hit the post, Pulisic almost added a second goal but had his shot cleared off the line by defender Kyle Walker after beating Ederson.
With just five minutes to play, Brazilian Willian earned the penalty that he converted for the winner that gave Liverpool the title with seven games to play.
The goal was the second in two games for Pulisic since the Premier League restart. He had been out for two and a half months with an adductor injury before European soccer was shut down in March. After a poor start following his move from Dortmund, Pulisic was outstanding for the Blues in October and November.
Chelsea manager Frank Lampard reiterated that Pulisic's lack of a summer break in 2019 because of the Gold Cup had set him back.
“Christian came in last summer," Lampard said after the City game. "Lot of talk about it. He didn’t really get a break when he got in the team. He was playing really well and gets a really tough injury."
The Chelsea manager added that he always intended to start Pulisic against City, just the 13th start in 31 league games, after he came off the bench with the first goal in the 2-1 comeback win at Aston Villa.
"I wanted to protect him a bit against Villa, see that he could make an impact," said Lampard. "He did that. I always planned to start him against Man City because I know what he can bring in these sort of games and he brought it. He did really well. He needs to keep working, he’s a young player but he’s got so much talent and he can get better and better.”