Chelsea ended a run of three consecutive defeats to rivals Barcelona with a 1-1 draw in the Women's Champions League, but were denied a second-half winner by offside.
Sonia Bompastor's team went ahead after 14 minutes at Stamford Bridge through Ellie Carpenter, but Ewa Pajor levelled shortly afterwards before a stoppage took place due to technical difficulties.
When play did get back under way, a cagey second half followed until a dramatic finale as Chelsea substitute Catarina Macario headed in with her first touch only to be denied by the offside flag in the 83rd minute before Carpenter dragged a gilt-edged chance wide.
It meant the hosts had to settle for a point against a team they have now defeated once in only eight meetings.
Chelsea are down to sixth in the league phase after four fixtures and outside of the top four which will earn automatic qualification for the quarter-finals.
Last season's painful 4-1 defeats in each semi-final leg were still fresh in the memory of Chelsea and Bompastor shuffled her pack after Sunday's disappointing 1-1 draw at Liverpool but Lauren James was again only on the bench along with captain Millie Bright.
Chelsea had failed to take the lead in each of their three previous contests with Barcelona, but a spectacular 16th-minute finish by Carpenter corrected that statistic.
After an even start, Carpenter exchanged passes with the bright Aggie Beever-Jones and the former Lyon full-back burst forward before she rifled the ball into the roof of the net.
It was a sensational strike, but Barcelona served up a strong response and equalised just eight minutes later.
Not long after Pajor had been denied by the offside flag, the Poland international swept home with aplomb after Claudia Pina's corner had not been cleared to make it 1-1 after 24 minutes.
The hosts responded strongly, with Wieke Kaptein denied by Cata Coll before the Chelsea forward went even closer when her stabbed effort hit the inside of a post and bounced to safety.
It was the last moment of note before a bizarre stoppage occurred after TV screens inside Stamford Bridge went down and referee Tess Olofsson subsequently experienced her own technical difficulties.
Play did eventually restart but despite nine minutes of first-half stoppage time, it remained level at the break.
A slow start to the second period was not helped when Chelsea's stand-in captain Erin Cuthbert needed treatment after a collision with three-time Ballon d'Or winner Aitana Bonmati, who had cut a frustrated figure.
Barcelona had taken charge by now, although chances remained limited and the hosts' threat on the break was highlighted after 63 minutes when Carpenter bombed forward again only to drag her effort wide this time.
Bompastor turned to her bench with 18 minutes left and it almost paid off instantly when Macario headed home Cuthbert's wonderful free-kick.
Chelsea celebration were immediately cut short after a quick VAR check showed Macario had been marginally offside.
Macario was involved again in the 81st minute when she laid the ball off for Carpenter, but the right-back dragged wide from seven yards.
