25 Sep 2020 5:22 PM +00:00

Juan Martin del Potro vs John Isner: US Open quarterfinal preview and prediction

(Photo credit: Marianne Bevis)

In a battle of the big men, 2009 US Open champion and world #3 Juan Martin del Potro takes on the last American man left standing John Isner for a place in the last four in New York. Earlier this season they split the Sunshine Double with del Potro winning in Indian Wells and Isner triumphing in Miami, and both also reached Grand Slam semifinals with del Potro making the last four at Roland Garros and Isner at Wimbledon. But who will come out on top?

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This will be the 12th meeting between Isner and del Potro. Seven of the previous encounters have gone del Potro’s way, four have been won by Isner. The first four matches were all won by del Potro until Isner snapped that losing streak in the Cincinnati semifinals in 2013. Over the past two seasons, they have met four times and shared the spoils. The Argentine claimed wins in Montreal last year and at Roland Garros this, whilst Isner won in Bercy in 2017 and in Miami in March.

Path to the quarterfinals

Despite not arriving in Flushing Meadows in the best of form, del Potro has been brutally effective so far. Donald Young was crushed 6-0 6-3 6-4 in the first round and his compatriot Denis Kudla fared little better in the second, losing 3-6 1-6 6-7 to del Potro. He then battled past Fernando Verdasco, who had beaten 2012 champion Andy Murray in four in the second round, 7-5 7-6 6-3 before beating 20th seed Borna Coric 6-4 6-3 6-1, though the Croatian was carrying a thigh injury.

Isner began his US Open campaign with a comfortable 7-6 6-3 6-4 victory over fellow American Bradley Klahn. He was pushed hard in the second round by the in-form Nicolas Jarry of Chile, but managed to win through, impressively winning the deciding set without losing a point on serve to triumph 6-7 6-4 3-6 7-6 6-4. He then ousted Serbia’s Dusan Lajovic 7-6 6-7 6-3 7-5 before knocking out Milos Raonic 3-6 6-4 6-3 3-6 6-2 in a match that rather astonishingly featured no tiebreaks.


How do they match up?

With both del Potro and Isner standing over six-and-a-half feet tall, Isner comfortably so, they are unsurprisingly equipped with serious power. For del Potro that power receives its most potent expression in the form of his forehand. It is his match-winner, and he has smashed through even the very best defences in the game with it. He has already hit 140 winners so far in New York and the vast majority have come from that forehand.

Isner’s best shot is unsurprisingly his serve, and he leads the tournament ace race with 112. That is 37 more than the second placed Raonic and 60 more than del Potro, who has a fine serve in his own right. His forehand is also a dangerous weapon even if it is not the equal of del Potro’s. But Isner’s backhand can be broken down and he is not as effective a returner as del Potro is. Those are areas that del Potro will look to target, but if Isner’s serve is firing he will take some serious stopping.


This has the makings of a very tight contest. Both men have big weapons and with the courts playing quite slowly, they will have time to wind them up. But, Isner will face the same problem in this match that he did against Anderson in the semifinals at Wimbledon, which is that del Potro can match him from the line and will beat him off the ground most of the time. Isner’s serve will keep him competitive, but expect del Potro’s variety and consistency to prove decisive. Del Potro in four.

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