Chelsea went down to Steaua Bucharest, while Tottenham Hotspur thumped Inter Milan in the Europa League on Thursday.
European champions Chelsea slumped to an uninspiring 1-0 loss at Steaua Bucharest in the first leg of their last-16 tie.
Raul Rusescu struck the decisive goal with a 34th-minute penalty after being brought down by Ryan Bertrand.
Chelsea offered little in response, with a dour performance leaving Rafael Benitez's men facing an uphill battle to reach the quarter-finals.
Meanwhile, Gareth Bale enjoyed a mixed encounter as Tottenham accounted for Inter 3-0 at White Hart Lane.
Bale opened the scoring with his 25th goal in 40 appearances this season, but will miss the return leg after being booked for simulation.
Gylfi Sigurdsson doubled the advantage in the 18th minute, before Belgian defender Jan Vertonghen put the result beyond doubt in the second half.
In other matches, Lazio took a significant step towards the last eight following a 2-0 victory at Stuttgart.
Ederson broke the deadlock against the run of play midway through the first half, while Ogenyi Onazi sealed a fine win with a stunning solo effort in the 56th minute.
Goals from Marcelo Diaz and Alexander Frei helped Basel to a 2-0 win over Zenit St Petersburg, who had Portuguese defender Nato sent off in stoppage time, in Switzerland.
A Cedric Carrasso own goal proved the difference in Benfica's 1-0 win at home to Bordeaux, while Anzhi Makhachkala and Newcastle United battled to a dull 0-0 stalemate in Russia.
Pierre Webo scored the decisive goal in Fenerbahce's 1-0 win at Viktoria Plzen, and Levante entertained Rubin Kazan in a 0-0 draw.