Antonio Colak's clinical first-half double set Rangers on their way to a comfortable 4-0 win away to 10-man Hearts.The 29-year-old Croatia striker's brace took his tally for the season to 11 goals since he joined from Malmo in the summer.Cammy Devlin's red card shortly before the break undermined the Jambos' hopes of a fightback before strikes in the closing quarter of an hour from substitute Alfredo Morelos and Ryan Kent sealed a morale-boasting victory for Rangers ahead of their Champions League trip to Liverpool on Tuesday (live on RTÉ2 and RTÉ Player).FULL MATCH DETAILSHearts manager Robbie Neilson made one tweak to the side that started the 3-0 win away to Motherwell last time out as Stephen Humphrys started instead of Andy Halliday.Rangers made two changes from the side that started the win over Dundee United a fortnight previously as youngsters Leon King and Charlie McCann made way for Rabbi Matondo and Ben Davies, who came back in for his first appearance since mid-August.The visitors had the first chance of the match after three minutes when Davies had a close-range effort deflected behind from a James Tavernier corner.Moments later, the same player saw his header from another Tavernier corner scrambled out by goalkeeper Craig Gordon.Rangers went ahead in the sixth minute when Colak headed in off Gordon's left-hand post after meeting a lovely Kent cross from the left.Hearts tried to find a response and Humphrys threatened with a couple of powerful strikes from outside the box.Scott Arfield had a great chance to double Rangers' lead in the 20th minute when he got in behind after Lewis Neilson - with the sun in his eyes - seemed to lose the flight of a ball over the top but the Rangers midfielder rolled his effort