The Spaniard went from creator to match winner in the Blues' game with Crystal Palace.
The Spaniard played a series of one-twos, first with Eden Hazard and then with Oscar before finishing past Julian Speroni in the Palace goal in the 51st minute.
Oscar had already given Chelsea the lead before each side suffered dismissals before half time. Fabregas's strike just after the break turned out to be the winning goal, with Frazier Campbell registering a consolation in the last minute for the home side.
The former Barcelona star scored 35 Premier League goals for Arsenal during his 8 years at the club, notching 57 times in all competitions over 303 games.
Fabregas carried his strong goalscoring form into his time back at childhood club Barca, where he scored 42 times in 151 games.
Gunners fans may not like the sight of their former hero scoring, and in a London derby no less, but given his record of finding the net, it is something they may well have to get used to.
Having already scored for the Blues in the Champions League game with Schalke, Fabregas's goal against Crystal Palace is sure to be only the first of many for the Blues in the Premier League.