In a jolting clash of massive servers, Reilly Opelka managed miniscule margins to topple John Isner.

The 6'11" Opelka unleashed his 40th ace to put the punctuation point on his 7-6 (4), 7-6 (8), 6-7 (4), 7-6 (5), triumph over the 6'10" Isner in the Australian Open first round.

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World No. 102 Opelka earned his first career Grand Slam main-draw victory in just his second major main-draw appearance. Two years ago, Opelka qualified for Melbourne bowing to David Goffin in five sets.

The ninth-seeded Isner suffered his sixth straight loss, a streak that dates back to the Paris Masters last October, and his second consecutive Australian Open opening-round exit.

Two of tallest men in the draw (Ivo Karlovic is slightly taller than Isner) combined for 87 aces in the two hour, 58-minute serving shootout.

It was Isner's first-evenrloss to a fellow American in Grand Slam play snapping his perfect 9-0 major record against compatriots.

The Miami Open champion  has been a tiebreak titan producing a .611 career winning percentage in tiebreaks, but Isner dropped to 1-5 in tiebreaks this season.  

Opelka, who played through qualifying to reach the Sydney round of 16 last week, will play 100th-ranked Italian Thomas Fabbiano next.

Photo credit: AP