Eden Hazard scored with a wonderful strike two minutes into added time to break AC Sparta Praha's resistance and propel Chelsea FC into the last 16 of the UEFA Europa League.
Chelsea's glory nights on the way to last year's UEFA Champions League crown seemed far, far away as new signing David Lafata's first goal for the Czech club enabled Sparta to tie the aggregate scores. Although the Blues held sway after that, Sparta always managed to get in a defensive block, edging towards extra time before Hazard produced his magic.
The hosts created early chances with Fernando Torres having three attempts at goal, coming closest when he stretched to reach Juan Mata's right-wing cross. It was not one-way traffic though, César Azpilicueta putting his body in the way just as Václav Kadlec pulled the trigger.
With Sparta employing three strikers high up the pitch Chelsea continued to defend with a degree of uncertainty. Following a quick free-kick in the 17th minute Kadlec did well to retain possession before laying the ball into Lafata's path, allowing the forward to score with ease and spoil former Sparta goalkeeper Petr Čech's 100th European appearance.
Chelsea responded and Mata improvised superbly to give himself a good sight of goal, but Tomáš Vaclík proved equal to it as the ball dropped just over the bar.
Ramires rampaged through after the restart and his drive was diverted onto an upright by Matěj Hybš. It was a let-off for the visitors but their own threat on the counter was underlined by Marek Matějovský who carried the ball a long way into the heart of the home rearguard before shooting wide.
Sparta had two late chances to win it but instead were undone at the death when Hazard brilliantly took out two defenders before finishing with a thumping left-footed effort.