After dropping out of the top 20 earlier in August, John Isner on Friday showed that he can still hang with the big boys, as the 28-year-old American upset No. 1 ranked player in the world Novak Djokovic in the quarterfinals of the Western & Southern Open in Cincinnati.

Having bounced back from a knee injury sustained in the second round of Wimbledon last month, Isner moved around the court with great confidence in his Nike Air Max Courtballistec 4.3 tennis shoes. After winning the opening set in a tiebreaker, Isner relinquished the following set before bouncing back to take the third and final set in a 7-6 (7-5), 3-6, 7-5 win.

Djokovic has had plenty of success on tour throughout his illustrious career. However, Cincinnati is one place he’s been unable to leave victorious. In fact, Cincinnati is the only Masters tournament that has eluded Novak.

There are currently no American men ranked in the top 20 for the first time in over 40 years. Isner, who currently sits at the 22 spot, can change that if he continues to play at top form.

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