25 Sep 2020 5:21 PM +00:00

Juan Martin del Potro vs John Isner: Miami Open semifinal preview and prediction

(Photo credit: Yann Caradec)

Indian Wells champion, Juan Martin del Potro, rides a fifteen match winning streak into his semifinal clash with the last American standing, John Isner. The Argentine is unquestionably the form player currently on Tour, and will be looking to add to the two trophies he has won already this year. Momentum seems to be building around del Potro and there are whispers of a second Slam becoming possible. Isner has turned around a wretched year in Miami and has contested three finals before at Masters level. Who will reach the final?

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Isner and del Potro have met nine times over the course of their careers. It is a head-to-head that del Potro leads six matches to three, and it was del Potro that won the first match in 2008 in the Washington quarterfinals 6-4 6-4. He won the next three meetings also, including in 2013 in the Washington final, where he recovered from dropping the first set to win in three. But Isner had his revenge in Cincinnati later that year, defeating del Potro in a tight semifinal encounter.

Isner won again at Queen’s on the resumption of their rivalry in 2016 after del Potro’s two year long absence with wrist problems. But del Potro then defeated Isner in their second match of 2016 in Stockholm, with the ‘Tower of Tandil’ going on to win the tournament. They met twice last season, splitting the wins one apiece. Del Potro got the first in Montreal in the first round, before Isner ended del Potro’s hopes of ATP Finals qualification in the Bercy quarterfinals.

Path to the semifinals

After receiving a first round bye, fifth seeded del Potro began his Miami Open campaign against Robin Haase. They split the opening sets, with a break in the first enough for del Potro to win it, whilst in the second it was Haase who had the better of it. In the decider, however, it was all del Potro as he broke twice to complete the victory. In the third round he brushed aside former top ten rival Nishikori 6-2 6-2 before accounting for 2017 Paris Masters finalist Filip Krajinovic 6-4 6-2.


Del Potro then clashed with Milos Raonic in the quarterfinals in one of the matches of the tournament. Whilst last week in Indian Wells del Potro had dismissed Raonic in the semifinals, their Miami clash was to prove quite different. Raonic drew first blood, winning the first set when del Potro buckled under pressure to double fault down set point. The next two sets were to be decided by tiebreaks despite a flurry of breaks at the start of the decider. Del Potro showed impressive mettle to win both.

Isner, seeded 14th, who came into the tournament with just two wins in 2018, picked up a much needed victory over Jiri Vesely in the second round after a hard fought battle. He backed that up with a more convincing win over Mikhail Youzhny who Isner beat 6-4 6-3. He then recorded his biggest win of the season against second seed Marin Cilic in straight sets to reach the quarterfinals. There he overcame young Korean Hyeon Chung 6-1 6-4 to reach his first semifinal of the season.

How do they match up?

Both men will rely on their power to win this match, particularly Isner. The giant American, who at 6’10 is one of the tallest ever to play on Tour, is at his best when he is able to keep the points short. Fortunately, he has the weapons to do so. His serve is one of the most formidable on Tour, with Isner’s height allowing him to strike the serve with power and utilise angles unavailable to shorter men. He can also hit his forehand with considerable venom.

But even Isner’s forehand doesn’t compare with del Potro’s. The world #6 possesses the biggest forehand on the Tour and arguably the biggest forehand of all time. However, del Potro’s is dangerous not only because of the power he is able to generate from it. He also excels at redirecting pace with his forehand as he showed with a 99 mph forehand winner off a Raonic return. That is versatility that Isner does not possess. The American is also substantially less manoeuvrable than his opponent.


Del Potro’s run hasn’t been entirely smooth so far in Miami, but nor was it in Indian Wells. What is crucial is that he seems to have that winning feeling, and it is helping him win through when the going gets tough. Isner, though he has found something of a winning spark of his own, won’t have enough to stop del Potro. The Argentine can move him around too much and has weapons that Isner’s limited defensive skills won’t be able to handle. Isner’s serve may keep him in it, but it won’t lead him to victory. Del Potro in three.

Who do you think will reach the final? Let us know in the comments below!