Chelsea are on collision course with Barcelona and Paris St Germain after they advanced to the Champions League last 16 - but only as runners-up - after being held by a streetwise Atletico Madrid in their final group game.
As it stands, Turkish side Besiktas are the only other possible opponents for the Blues in the knockout stages.
Chelsea had dominated until the opening goal, with Alvaro Morata going close and Eden Hazard almost weaving through the visiting defence.
But Saul Niguez escaped the attentions of Tiemoue Bakayoko to plant home a header from Fernando Torres' near-post flick-on after 56 minutes.
Chelsea piled forward as time ebbed away, and Stefan Savic turned Eden Hazard's cross into his own net as the pressure told.
But, with Roma beating Qarabag in the Italian capital, Chelsea could not find the second goal and the victory needed to regain the lead in Group C.