John Isner in Western and Southern Open final

A contest between the towering 6ft 10in Isner and the 6ft 6in Del Potro was always going to be a bruising baseline battle and it lived up to predictions as the two giants slugged it out for two hours and 47 minutes.

The semi-finals had a dramatically different look from what tennis fans might have hoped, with the ATP Tour’s “big four”; world No.1 Novak Djokovic, No.2 Andy Murray, No.3 Nadal and five-time Cincinnati champion Roger Federer all featuring in the last eight. But after a day of upsets that saw only Nadal survive, the partisan crowd still had plenty of reason to cheer as Isner carried the US flag into the semi-finals, picking up his first career win in five tries against the seventh seeded Argentine.

Isner, pictured, who delivered the biggest shock of the quarter-finals toppling Djokovic, has traditionally saved his best for the home crowd with 13 of the his 15 career ATP Tour final appearances coming in the US and he proved once again to be a crowd pleaser, pounding 23 aces past his opponent.

Since retiring in the second round at Wimbledon with a left knee injury, Isner has been in sizzling hardcourt form, putting together a 15-3 match record while picking up his seventh career title in Atlanta followed by a runner-up finish in Washington.

In a tight opening set that failed to produce a break, it was Del Potro taking the initiative winning the tiebreak 7-5. The 2009 US Open champion had looked poised to end the contest in two sets serving for the match at 5-4 only to double-fault on match point opening the door for Isner. The 28-year-old American seized his chance but it was not easy needing five set points before clinching the tiebreak 11-9. Isner rode that wave of momentum from his tiebreak into the third set, breaking Del Potro at the first opportunity and pulling in front 3-0 on his way to a hard fought win.