David Luiz's free-kick deep in injury-time handed Chelsea a 2-1 first leg Europa League semi-final win over FC Basel, while the other tie saw Fenerbahce beat Benfica 1-0.
Last season's Champions League winners Chelsea went in front against FC Basel when Branislav Ivanovic - victim of Luis Suarez's bite - won a header which went in off Victor Moses, who claimed his third goal in as many Europa League games.
The visitors should have scored again prior to Fernando Torres striking the post before Cesar Azpilicueta was adjudged to have fouled Valentin Stocker and Fabian Schar converted an 87th-minute penalty.
However, Chelsea responded and Luiz's late intervention earned the advantage ahead of next week's return at Stamford Bridge.
A solitary goal by Egeman Korkmaz guided Fenerbahce to a narrow 1-0 victory in the first leg of their Europa League semi-final against Benfica in Istanbul .
Korkmaz's goal 18 minutes from time was scant reward for Fener, who could have taken a more commanding lead to Portugal after Cristian Baroni hit a first-half penalty against the post, while Moussa Sow and Dirk Kuyt also rattled the frame of the goal.