You are right, Manchester United indeed dominated the match but they were lucky because Casemiro scored in the 94th minute
Chelsea should have managed to get 3 points but all disappeared in the final minutes

but yeah 1-1 is fair enough for both teams
who would have thought that minutes are crucial for Casemiro, he is a hero. The game was boring enough without a convincing attack for each other between 80', maybe waiting for a counterattack but using a bad time strategy until McTominay exaggerates to violate Broja. After a penalty, Chelsea should have pulled back all players so don't let Casemiro go roam the penalty area.
Manchester United played really well in this match. Chelsea had almost no attacking position. McTominay brought Chelsea a penalty out of nothing. Kepa, the goalkeeper who saved Chelsea, could not prevent the position in the last minutes. Actually, Chelsea are lucky to have won 1 point. Manchester United came very close to 3 points in this match.