There was an end-to-end flow to the game in the first half but it was the visitors who provided the quality moments in the final third with the Croatian international scoring his eighth and ninth goals for the club after joining in the summer.
It provided the team with the perfect platform prior to Cammy Devlin’s red card with Alfredo Morelos and Ryan Kent adding goals three and four.
“Apart from his goals, he is very important the way he puts energy in the team,” Van Bronckhorst said of Colak. He scored in the last game two goals also and today again.
"Really happy with him. And also to see Morelos and Kent also on the scoresheet. We want to improve our chances and improve our goals and it is good today for Alfredo and Ryan to be on the scoresheet.
"Of course to win 4-0 away against Hearts is a big win for us. We have started well in the last block before the World Cup.
"You always know it is going to be a difficult place to go but I think we started really well and the first goal is always important. In the last meetings here we always did it and today as well.
"Of course they have to trail you so that was good. Second goal was a great goal. We made before that some good transition moments and I think we should have scored one or two.
"In the end we didn’t have the right pass or a bit too much speed and in the second half we are playing with eleven so it is more difficult for them to press us. We controlled the game and managed to score two goals.”
Davies sub and Devlin chat
Van Bronckhorst explained the reasoning behind replacing Ben Davies with James Sands at half-time following the summer signings first appearance since August.
“He was OK”, the Dutchman said. “He was on a yellow and of course with all the balls in our backline in the second half, we decided to put James on and make sure we were staying with eleven this time.”
The Rangers boss was animated towards the end of the half when Cammy Devlin put a strong challenge on Rabbi Matondo which earned the Hearts midfielder a deserved red card.
Van Bronckhorst spoke of his admiration for the Australian midfielder revealing what he told the player as he left the pitch.
"It was just before me,” he said. “Rabbi was in battle with his opponent and he came from behind.
"I really like him as a player, I told him you don’t need these challenges, you are a far better player than he showed today. He is one of their best players, he is a midfielder with dynamics. I told him he doesn’t need these kinds of challenges.”
Rangers now travel to Liverpool to face the English giants in their third Champions League encounter.
"It was important to get the start we had today and to get the three points,” he said. “It is very positive. Now we have two days to prepare for a big game at Liverpool.”