Colak found the target on the hour mark to secure a 1-0 win at PSV Eindhoven and seal a 3-2 aggregate victory in their play-off.
Champions League: PSV rescue Rangers draw as Armando Obispo spares Walter Benitez's blushes in play-offs
Although PSV will be favourites on home turf, Rangers should still fancy their chances after staging a rousing comeback to defeat Union Saint-Gilloise
Eintracht Frankfurt defeated Rangers 5-4 on penalties to win the Europa League on Wednesday after the final in Seville finished 1-1 at the end of extra time.
Rangers are seeking their first piece of European silverware since 1972 and Eintracht Frankfurt are hoping to end their 42-year barren run when they meet in the Europa League final.
Rangers overturned a 1-0 deficit from the first leg by defeating RB Leipzig 3-1 at a raucous Ibrox Stadium in Glasgow.
West Ham United and Rangers must both overturn first-leg deficits against German opposition on Thursday if they are to reach the Europa League final.
Xavi Hernandez's Barcelona, playing in Europe's second-tier competition for the first time since 2004, dominated for long periods but could not find the winning goal.
The one remaining English Premier League representative in the competition, West Ham will go to Seville for the first leg on Thursday, March 10 before hosting the return a week later.
Barca needed a Ferran Torres penalty to draw 1-1 at home to Napoli in the first leg of their knockout round play-off tie after Piotr Zielinski put the Serie A side in front at the Camp Nou.
In the Europa Conference League, Celtic had a less distinguished evening than their Glasgow rivals, losing 3-1 at home to Norway's Bodo/Glimt.
The Catalans crashed out of the Champions League in the group stage with just two goals scored in six matches
Xavi Hernandez's Barca will continue their European campaign in the second-tier competition, with the winner of their tie with Napoli advancing to the last 16.
Real Betis, Lazio, Monaco, Galatasaray and Olympiakos also qualified for the knockout stages on Thursday.
Gerrard was hired as Villa boss last week after agreeing to leave Scottish champions Rangers.
Gerrard guided Rangers to the Scottish Premiership title last season.
Leicester have work to do after being held 1-1 at home by Spartak Moscow.
Europa League: Leicester City, Napoli suffer shock defeats; race row mars Rangers-Sparta Prague game
A much-changed Leicester went down 1-0 to Legia Warsaw in Poland, while Napoli's unbeaten record this season was ended by Quincy Promes' double for Spartak Moscow in a thrilling 3-2 win for the Russians at the Diego Maradona stadium.
National women's football team striker Bala Devi, who is currently playing for Rangers in the Scottish Women's Premier League, has been recommended for the coveted Arjuna Award.
Rangers FC’s Bala Devi reveals struggles during lockdown in Scotland, credits club for turning things around
Over the course of the past couple of months, Bala Devi has gone from strength to strength, and has become a vital cog in a Rangers side that is currently second in the SWPL table.
Fans ignored pleas from the club and government to disperse as they then marched from Ibrox into Glasgow city centre.