Eden Hazard scored with virtually the last kick of the match to give Chelsea a fortunate 1-1 draw against Sparta Prague at Stamford Bridge that sees them into the Europa League last 16 with a 2-1 aggregate victory.
But this was a close run thing for the Champions League holders, who began the match as 5-1 favourites to win the tournament, but ended it looking a bedraggled lot with Spain striker Fernando Torres enduring another miserable night in front of goal.
Hazard broke the spirit of a superbly organised Sparta side when he danced away from a couple of tiring opposing players to send a bullet of a finish bounding beyond the helpless Tomas Vaclik in the Sparta goal.
Sparta had struck the opening goal on 17 minutes when David Lafata crashed his finish into the gaping net after the impressive Vaclav Kadlec had outmuscled Gary Cahill to play provider for his team-mate to score.
Torres wasted several chances to bury the threat of the visiting side, and it was left to Hazard to rescue Rafael Benitez's side when he replaced first-leg match-winner Oscar on 68 minutes.
It may well have rescued Benitez's position as Chelsea coach for the time being after his side almost threw away the 1-0 win they constructed in Prague last week courtesy of Oscar's goal.
This was a performance lacking in any real authority, but at least Chelsea have the consolation of joining Tottenham and Newcastle in the last 16 despite doing little of note with their dollops of possession.
Chelsea's reward is a meeting with Steaua Bucharest, who beat Ajax 4-2 on penalties after their tie ended 2-2 on aggregate, but they will have to play much better than this to keep alive their hopes of becoming only the fourth side in history to win all three of the UEFA club tournaments having already claimed the Champions League and now defunct Cup Winners' Cup.
With holders Atletico Madrid departing the tournament after a surprise 2-1 aggregate defeat at Rubin Kazan, Chelsea - minus the rested Frank Lampard who netted his 199th goal for the club against Brentford on Sunday - began the evening aware of the prospects of a second European trophy in successive seasons.
But the images of their penalty shoot-out win over Bayern Munich in the Champions League final nine months ago seemed a long way off as Torres was found sadly wanting for large swathes of a contest watching by 3,000 Prague fans in a crowd of almost 40,000.
The £50 million man slid a Victor Moses cutback wide of the goal on four minutes before somehow managing to lift a Juan Mata cross over when it seemed easier to score from five yards out on 10 minutes.
Lafata made Chelsea pay when he levelled the aggregate score, but the home side continued to toil to cut through Sparta with Vacklik making a fine stop to nudge a volley over after Mata had been sent through on goal by Ramires.
Chelsea's situation remained parlous as Torres raced onto a pass from Ramires only for Vaclik to come off his line to make a fine block while Ramires saw a deflected shot hit a post moments earlier as the home fans continued to project a mood of discontent.
Sparta always remained a threat on the break and Marek Matejovský was left wondering what might have been when he drove a shot wide of goal from distance on 63 minutes with Petr Cech clearly beaten.
As the clock headed for injury time Kadlec sliced an effort wide of goal before Cahill came up with a timely block to deny the Czech Republic forward seconds. It scarcely seemed believable that Chelsea would find the goal they craved, but Hazard felt otherwise as he finished off a home break with a goal of real quality.
MAN OF THE MATCH
Eden Hazard - Chelsea: Kept his head when all around him were losing theirs. Deserves the award for potentially keeping his manager in employment - until the summer at least.