Chelsea were controversially denied back-to-back victories in Champions League Group E when they were held 1-1 by Valencia on Wednesday.
Andre Villas-Boas men took the lead at the Mestalla in the 56th minute, when English midfielder Frank Lampard scored his first European goal since October 2009.
Lampard powered home a trademark strike that looked to have sealed the Londoners their second win in the group.
But a late penalty paid by referee Nicola Rizzoli was converted by Roberto Soldado in the 86th minute, much to the delight of the La Liga club s faithful.
However, the referee s decision caught the ire of the English Premier League side, protesting the guilt of Salomon Kalou after he was judged to have handballed in the area.
The decision came after Rizzoli failed to send off Valencia s Victor Ruiz, who brought down Ramires when the Brazilian was through on goal.
Ruiz received a yellow card for the foul.
Chelsea s continued protests at Rizzoli saw Lampard, Ashley Cole and former Valencia attacker Juan Mata all receive yellow cards in the dying stages.
Chelsea top the group on four points, one ahead of Bayer Leverkusen, after the Bundesliga outfit accounted for Belgian First Division club Genk 2-0.
Leverkusen broke the deadlock in the 29th minute, when Lars Bender tucked a strike past Genk shot-stopper Lazslo Koteles and into the bottom left corner .
Michael Ballack s deflected strike in second-half injury time doubled their lead, with Koteles getting a hand on the ball but not being able to keep it out of the net.
