Athletic Bilbao cruised to a 3-0 win over Elfsborg on Thursday to move level on points with Lazio at the top of the Europa League table, while Chelsea made it four wins from four in the Conference League.
The win keeps unbeaten Leverkusen's dream of a remarkable treble alive, with Xabi Alonso's side 10 points clear in the Bundesliga with nine games to play and in the German Cup semi-finals.
Chelsea head Group L with a maximum six points with PAOK level on three points alongside BATE Borisov.