Murray lost the first set against Muller and was facing two break points to go 5-3 down in the second before clawing his way back to win 4-6, 7-6 (7/4), 6-0 in two hours exactly. The 24-year-old Scotsman was in similar trouble against Mikhail Kukushkin in the first round before recovering and will be desperate to avoid another slow start against Cypriot Marcos Baghdatis in the quarter-finals.
"I felt I moved better in the second and third sets and that's such a big part of my game," a relieved Murray said. "I was happy to get the win -- the more matches I can get this week, the better. I thought once I got into the baseline rallies I felt good but he served very well, especially for the first couple of sets and I just managed to hang in." The world number four Murray, who is eyeing his first Grand Slam at the Australian Open in less than two weeks, started well and looked in complete control throughout much of the first set.