It only took three minutes after the halftime break for Manchester City to respond down a goal.
With Fernando Torres having teed up Andre Schurrle for the opener in the 33rd minute, Manchester City pulled back level.
Sergio Aguero made a run down the left-hand side, got the feed from Samir Nasri, and rocketed a pinpoint shot into the top left corner to equalize at 1-1.
Chelsea goalkeeper Petr Cech was left wrong-footed, and barely made an attempt to stop the shot as it tucked into the tight corner.
The goal from Kun is a great sign for City – the Citizens are unbeaten in 31 Premier League matches when Aguero scores, having won 29 and drawn two.
With Chelsea pressing most of the first half thanks to a physical presence in the midfield and a lot of possession, the second half has been all City. Javi Garcia also tested Cech on a set-piece header, but it was caught and held by the keeper.