Celtic are top of Europa League Group E, with seven points from nine, and are in Rome to face Lazio on matchday four, kick-off 5.55pm.
Neil Lennon's side earned a 2-1 win when the sides met at Parkhead a fortnight ago and go into the game on the back of a 5-2 victory over Hibernian in the Betfred Cup semi-final.
Steven Gerrard's men have already beaten Feyenoord at Ibrox and now host Porto, kick-off 8.00pm, having drawn 1-1 in Portugal two weeks ago.
Rangers were 3-0 winners against Hearts in Sunday's Betfred Cup semi-final at Hampden.
Both of tonight's games are live on BT Sport.