Serie A title challengers Napoli were stunned 3-0 at home by Czech club Viktoria Plzen as Russia's Anzhi Makhachkala and Zenit St Petersburg opened up commanding first-leg advantages in their Europa League last 32 ties.
Goals from Vladimir Darida, Frantisek Rajtoral and Stanislav Tecl upset Napoli while Anzhi beat Hanover 3-1 and Zenit won 2-0 at home against five-times European Cup winners Liverpool.
Brazilian Oscar spared European champions Chelsea's blushes late on against Czechs Sparta Prague to give the Londoners a 1-0 lead to take back to Stamford Bridge for the second leg next Thursday.
Samuel Eto'o, four-times African player of the year who has won the Champions League three times with Barcelona and Inter Milan, was on target and missed a penalty for big-spending Anzhi after Hanover had taken the lead midway through the first half.
The German visitors drew first blood when Hungarian Szabolcs Huszti scored only for Eto'o to level after 34 minutes and Odil Akhmedov to put Anzhi in front three minutes after the restart.
Eto'o missed a penalty just short of the hour mark but Mbark Boussoufa gave the Russians a sizeable 3-1 lead after 64 minutes.
"We played a good match considering we're only in the third week of preparation (for the re-start of the Russian league season) while our opponents have their season in full swing," Anzhi coach Guus Hiddink told Russian television NTV Plus.
Hulk's unstoppable swerving effort from 30 metres broke the deadlock for Zenit after 69 minutes and Sergei Semak poked home three minutes later to break Liverpool's resistance after the Premier League club's striker Luis Suarez had spurned several chances.
"He (Suarez) could have had a hat-trick by halftime," Liverpool manager Brendan Rodgers told ITV.
"It wasn't his night. The positive we take into the next game is that if we can be solid defensively we can create some chances next week. I feel we're more than capable of that," added Rodgers.
Darida was on hand to crash the loose ball into the net after 28 minutes against Napoli, second in the Italian league and who were not taking the competition lightly as forwards Edinson Cavani, Marek Hamsik and Goran Pandev all played.
Rajtoral crept in unnoticed at the far post to bundle the ball past Italian international Morgan De Sanctis with 11 minutes remaining while Tecl added a third late on to give Czech league leaders Plzen a famous victory.
Chelsea, who dropped into the Europa League after being dumped out of the Champions League as holders in the group stage, fielded an equally strong side with Frank Lampard, Juan Mata and Eden Hazard all featuring though misfiring forward Fernando Torres had another game to forget.
The English club flirted with a 0-0 draw until substitute Oscar's 82-minute winner shortly after coming on.
"Sparta played well which made it good. It was a strange experience and I'm glad we got that one goal at the end," said Chelsea and Czech Republic goalkeeper Petr Cech, formerly a Sparta player.
There were impressive wins for Spanish club Levante, who beat runaway Greek league leaders Olympiakos Piraeus 3-0 at home and Ajax Amsterdam, 2-0 victors against former European champions Steaua Bucharest in the Netherlands.
Champions League dropouts Benfica won 1-0 at German club Bayer Leverkusen, Oscar Cardozo on target for the Portuguese just after the hour while Dynamo Kiev and Girondins Bordeaux shared the honours in a 1-1 draw in Ukraine.
Belarussians BATE Borisov drew 0-0 at home with Fenerbahce, who were reduced to 10 men after four minutes when Portuguese midfielder Raul Meireles was sent off.
Meireles had an 11-match ban for spitting at a referee in the Turkish league in December reduced to four games on appeal.
Europa League holders Atletico Madrid were hosting Russians Rubin Kazan in one of the late kickoffs.
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