But the 20-year-old showed his vulnerability when he tried to serve out the first set at 5-4 and instead let three set points sail past as Murray dug

Third seed Venus Williams moved through to the quarter-finals of the Zurich Open with a determined 6-3 6-4 victory over Alona Bondarenko of Ukraine.

The 28-year-old needed to save a total of four break points in the match, one in the first set and three in the next.

"I played OK and when the points became important I was winning those, especially on my serve," she said.

Italian Flavia Pennetta set up a clash with top seed Jelena Jankovic after thrashing Nadia Petrova 6-1 6-1.