Juan Martin Del Potro rallies to beat racquet-smasher Alexander Zverev in Shanghai Open

The Argentine fought back from a set down to beat rising star Zverev 3-6, 7-6, 6-4 in the quarterfinals.

Shanghai: Juan Martin del Potro fought back from a set down to beat racquet-smashing rising star Alexander Zverev and reach the Shanghai Masters quarterfinals on Thursday.

The seasoned Argentine recovered to win 3-6, 7-6 (7/5), 6-4 in one hour, 55 minutes against the 20-year-old Zverev and will next play either Viktor Troicki or John Isner.

Zverev was going after his sixth title of an outstanding season and was comfortable in the first set against del Potro, the 2009 US Open champion.

The German prodigy and the 29-year-old, whose career has been beset by injury, went toe to toe in the second set and the tie break was just as tight until del Potro grabbed the crucial mini-break.

And then came the turning point - and the flash of anger from third seed Zverev - as he yielded the crucial service break to go 3-2 down in the third set.