Paris Saint Germain crashed to a 4-2 defeat at home to Hapoel Tel-Aviv.
Salim Toama opened the scoring for Hapoel after just two minutes and then stunned PSG with a brilliant second from outside the area just four minutes later.
PSG battled back onto level terms through Pierre-Alain Frau (14) and Pauleta (25), but they soon fell behind again.
Walid Badir made it 3-2 to the Israeli side with a shot into the bottom corner following Toama's corner (44), before Elyaniv Barda secured the victory with another fine goal after 57 minutes.
In Group G's other game, Rapid Bucharest came from behind to draw 1-1 with Mlada Boleslav.
Czech side Mlada Boleslav opened the scoring three minutes before half time as Jan Rajnoch headed home Marek Kulic's cross.
Marius Constantin equalised for Rapid Bucharest in the 52nd minute, tucking away the rebound after Miroslav Miller had saved Viorel Moldovan's effort.
The result leaves both sides perilously placed in the group, with Rapid on three points from three games and Mlada Boleslav on one point from two games.
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