Cristiano Ronaldo has adapted seamlessly since joining Juventus but Massimiliano Allegri is ready to give the 33-year-old a break.
Celtic were able to breathe a sigh of relief as they advanced from Group B in the Europa League despite losing to Red Bull Salzburg.
A mistake by Allan McGregor led to Rapid Vienna's winner as Rangers lost 1-0 and went out of the Europe League at the group stage.
AC Milan boss Gennaro Gattuso insisted there are no easy games in the Europa League after a nervy encounter with unheralded Dudelange.
Emile Smith Rowe scored as Arsenal won away to Vorskla, with Unai Emery hailing the young midfielder's impact.
After Arsenal's meeting with Vorskla was switched from Poltava to Kiev, Gunners head coach Unai Emery supported UEFA's decision.
Olympiacos secured progression into the Europa League knockout stages at AC Milan's expense thanks to a 3-1 victory in Athens.