Tennis: Andy Murray Through to Quarter-finals of Sap Open

British No1 Andy Murray edged through to the quarter-finals of the SAP Open with a 6-0, 6-7 (5-7), 6-4 victory over Denmark's Kristian Pless.

The third seed and defending champion, who disposed of American Kevin Kim 6-3, 6-1 in the first round on Tuesday, wasted little time in wrapping up the first set but was forced to regroup after the world No83 took the second on a tie-break.

"I felt a little sluggish but I wasn't playing badly," said Murray. "I was able to get through and on this court I was able to keep the ball down. I started to come at the net a little bit. I felt like I had to try some different things. My serve kept me in the match today. I didn't return as well as I normally do and my groundstrokes weren't that solid. Obviously, it's nice to get through. He played a good match."

Murray raced into a one-set lead, winning eight out of nine first serve points played, but the 26-year-old Dane made him work hard for his second break in the fourth game. The Scot then quickly rattled off the two remaining games he needed to claim the set.

Pless responded well and had three break points on the Murray serve at the start of the second set, eventually converting the third of them. Murray restored parity with a break in the sixth game, which progressed to a tie-break, but Pless held his nerve to level the contest.

The 19-year-old survived break points in game six of the deciding set and demonstrated his character to break his opponent shortly afterwards and move 4-3 up, before serving out successfully for the match as Pless hit two consecutive backhand service returns over the baseline.

Murray will face either Simon Greul or Hyung-Taik Lee in the last eight.