Sergio Aguero had the chance to put Manchester City 2-0 up over Chelsea from the penalty spot but missed embarrassingly.
City were already 1-0 up through Raheem Sterling when they were awarded a spot-kick shortly before half-time.
The Blues striker stepped up to take it knowing that converting it would put his side within touching distance of clinching the Premier League title.
But his weak attempt at a Panenka-style penalty dropped into the hands of grateful Chelsea goalkeeper Edouard Mendy.
Aguero immediately sheepishly looked over to the bench, where manager Pep Guardiola was visibly annoyed.