Stuttgart, Germany, 11 June 2015 | tennis.com.au

Sam Groth has stunned third seed Feliciano Lopez to advance to the quarterfinals of the ATP grasscourt event in Stuttgart.

Groth recovered to beat the renowned grasscourter 3-6 7-6(5) 7-6(6) in a touch over two hours on Wednesday.

The Aussie slammed 19 aces en route to the biggest victory of his career – and his seventh straight – against an opponent currently ranked 14th.

He will next face No.8 seed Victor Troicki of Serbia.

Lopez, unlike many of his Spanish compatriots, is a dashing serve-and-volleyer who prefers the slick lawns of England.

The 33-year-old has won two Eastbourne titles on grass (2013 and 2014) and three times reached the Wimbledon quarterfinals. He also reached the Queen’s final in 2014.

This is the fourth ATP quarterfinal of Groth’s career; his best ever performance on tour was advancing to the semis in Newport in 2014.