Murray marks 10th anniversary of US Open breakthrough with victory
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The 35-year-old Murray defeated the 24th seed 7-5, 6-3, 6-3, showing no signs of recent cramping problems which plagued his hardcourt summer.
"They were very tricky conditions, very hot and humid. Just really happy to get through that one."
Murray won the first of his three Grand Slams at the US Open in 2012, ending Britain's 76-year wait for a men's champion at the majors.
"It seems like a long time ago when I won here. A lot has happened in my career since then but it was huge moment for me."
Now ranked 51, Murray will face either Australia's John Millman or American wildcard Emilio Nava for a place in the last 32.