The duo shared four breaks of serve in an opening set that was taken to a tie-breaker by the Austrian world No. 68 and who fought back from 5-0 down to 6-6 in the first-set decider.
The second set was just as frustrating for the world No. 1 despite him hitting 10 aces and seeing 78 percent of his first serves in — but he edged past the 26-year-old to set up a meeting against Spain’s Nicolas Almagro.
“He played great, great tennis and was dominating large parts of the match,” said Murray. “He made it extremely, extremely difficult. I was a bit lucky to through in two sets today. I think he’s playing much better than someone ranked 69 in the world.
“Today was a perfect example of the depth in the men’s games just now. I actually played pretty good, but he was hitting the ball huge from both sides. You need to be ready for every single match.”
World No. 44 Almagro sealed his place in the last eight with a 7-6(5) 7-6(6) straight-sets success over Germany’s Philipp Kohlschreiber.