World number three Juan Martin del Potro needed four sets but overcame John Isner to make it to the US Open semi-finals on Tuesday night.
The 2009 champion Del Potro has yet to drop a set in this year’s tournament, and should be fresher than Isner who has twice been taken the full distance, first by Nicholas Jarry of Chile and then, in the fourth round by Milos Roanic, which saw the American win the battle of the big servers.
This will be the twelfth time the men have met, with Del Potro leading the series 7–4, although two of the last three meetings have been in favour of Isner, with both victories coming on hard courts.
For the American, the key to success as ever, lies with his serve, He has served 112 aces in the tournament so far, 37 more than the next placed man and nearly double those produced by Del Potro – who is a fine server in his own right.
If he can serve well and consistently, he will always have a chance. His other effective weapon is his forehand, but he has a weakness on his backhand side, and he is not as effective a returner of serve as the Argentine.
Del Potro is strong on both sides, particularly his forehand side, and he has already hit 140 winners since the tournament started. He has the better all-round game of the two men, and can expect to command the back of the court.
One possible doubt over the match comes from an unexpected source. Isner’s wife is heavily pregnant, and although the baby is not due until September 22, should it choose to make an early appearance, Isner may have to choose between missing the birth or missing the match.
Hopefully for the spectators and fans, baby Isner will delay his arrival so father to be can play this match. Del Potro starts favourite to win because he has more shots at his disposal than his opponent, but, if Isner serves to his full potential, then there may yet be a surprise.
The match will take place on Tuesday but tournament organisers have yet to announce the order of play and scheduling.