An unconvincing Real Madrid needed a controversial Cristiano Ronaldo penalty deep into stoppage time to snatch a 2-1 win at promoted Elche on Wednesday that kept them hard on the heels of La Liga leaders Barcelona and Atletico Madrid.
Red Star Belgrade, who won Europe's premier club competition in 1991, engineered a 2-0 home victory against HJK Helsinki thanks to a Richmond Boakye header and substitute Milan Pavkov's sweeping 90th-minute finish.
Azeri champions Qarabag took a big step towards the playoff round with a 2-1 win at Cypriot side APOEL but Dinamo Zagreb left their progress hanging in the balance after the Croats played out a 1-1 home draw against Hungary's Ferencvaros.
Ajax, semi-finalists last season, came from behind to beat PAOK 3-2 for a 5-4 aggregate win over the Greeks while Red Star knocked out FC Copenhagen on penalties after a bizarre shootout involving 22 spot-kicks.
Arsenal led a list of nine clubs who grabbed a second win in as many games in the Europa League group phase as France striker Olivier Giroud scored his 100th goal for the club in a 4-2 win at BATE Borisov on Thursday.
Inter Milan staged a late smash-and-grab raid as goals by Mauro Icardi and Matias Vecino secured a 2-1 home win over Tottenham Hotspur in their Champions League Group B opener on Tuesday.
Images from the UEFA Champions League matches played on Tuesday.
Andy Murray clinched the Vienna Open title on Sunday with a 5-7, 6-2, 7-5 victory over David Ferrer, one of the Briton's main rivals in the battle to qualify for the ATP World Tour Finals.
