A week after losing to Richard Gasquet in Cincinnati - Murray’s first singles match since January – the former world No 1 fell 7-6(8) 7-5 to Tennys Sandgren in the first round at Winston-Salem.
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The 32-year-old was edged out in a tight first set after no breaks of serve, with Sandgren converting his fourth set point in the tie-break after Murray missed one opportunity.
Murray was then broken twice to fall 3-0 down in the second set, and though he rallied back to 5-5, Sandgren closed out the match by winning the next two games.
"I'm quite aware of sort of where I'm at just now and what my level is. It's competitive at this level but it needs to be better," Murray told the ATP’s website, having sent down a first-serve percentage of 50%.
"Maybe I need to play a level down to get some matches and build my game up a little bit before I start playing on the Tour again."
Murray opted against playing in next week’s US Open as he carefully manages his return from hip resurfacing surgery, pulling out of the doubles after initially deciding against the singles.
The three-time Grand Slam champion could look at playing one or two Challengers in the coming fortnight, while he is already scheduled to play two ATP events in China next month.
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