Murray shared that he can only keep focused and wait for tougher challenges to come in the latter stages ahead of a quarter-final clash with Jeremy Chardy.
He told reporters: "It was tough to gauge how well I hit the ball. You have to work harder on your feet and concentrate on every shot on this surface.
"Anyone who has seen Chardy play this week will see he has a big serve and plays aggressive with a big forehand. He can be a bit erratic at times but it could be really tough match."
The Scot is yet to drop a set in the tournament and remains second favourite with the bookies to clinch the season's opening Grand Slam.