Third seed John Isner was bundled out of the US National Indoor Championships in Memphis at the first opportunity, with Denis Istomin sealing a straight-sets victory
Isner was beaten 6-4, 6-3 by his Uzbekistani opponent, ranked number 63 in the world.
There were three American winners on the day to make up for Isner’s exit.
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Fourth seed and 2010 champion Sam Querrey defeated Colombian Alejandro Falla 6-3 6-3, James Blake edged Florian Mayer 4-6 6-3 6-2 and Michael Russell was a 6-2 6-4 winner over Alex Bogomolov.