The Blues took a slender 1-0 lead into the break after a tight first 45. The away side took the lead early on through an Azpilicueta tap in following a scramble from a corner,
But after that there was little to separate the teams. Both struggled to establish any fluency going forward, but towards the end of the half, Brighton began to build a little pressure with Kepa saving well from a fierce Trossard effort.
Nevertheless, Chelsea looked well-organised defensively and just about deserve their lead.
84th minute, Jahanbakhsh nets a late leveler with a stunning bicycle-kick. Brighton swing another corner into the box that Dunk nods out towards Jahanbakhsh, who acrobatically swivels in the air before guiding an unstoppable volley into the bottom corner.
Frank Lampard will surely be furious with his side as they dropped two points away from home.
The result means that Brighton climb to 13th as they continue to edge away from the relegation zone.
Chelsea, meanwhile, extend their lead over fifth to five points but both Manchester United and Tottenham will eagerly see this as an opportunity to reel them in slightly today.