Rangers stormed back from two goals down to beat Braga 3-2 at Ibrox thanks to goals from Ianis Hagi (2) and Joe Aribo.
Steven Gerrard's men now travel to Portugal for the second leg on Wednesday as they bid for a place in the last 16.
Celtic drew 1-1 with Copenhagen in Denmark - Odsonne Edouard scored for the Hoops and Fraser Forster saved a second-half penalty.
Neil Lennon's team welcome the Danish side to Glasgow for the return leg on Thursday.
