Juan Martin del Potro, the 2009 US Open champion who in the intervening years had four wrist surgeries that displaced him from the top of the men’s game, ensured that yet again there would be no meeting of Rafael Nadal and Roger Federer in New York.

Delpo backed up his remarkable, come-from-behind fourth-round victory over Austrian Dominic Thiem and defeated the No. 3 seed Federer, 7-6, 3-6, 7-6, 6-4 – the same Swiss whom long ago the Argentine upset in that memorable ’09 final.

Now it is the tall and popular del Potro, rather than “The Maestro,” who advances to meet the top-seeded Nadal in the semifinal on Friday.

Del Potro survived an improbable and crucial third-set tiebreak, including four set points on Roger Federer’s racquet, to win in two hours and 50 minutes.