Three-time Grand Slam champion Stan Wawrinka exited the Rome Masters on Thursday. Big-serving American John Isner surprised the 32-year-old, reaching his first quarter-final in Rome. The world number 24 needed just two sets to outclass the number three seed from Switzerland 7-6 (7-1) 6-4.

Isner fired 19 aces in an hour and 25 minutes of action. The unseeded player broke the serve of Wawrinka once during the match and saved each of Wawrinka's five break point chances. Isner now has a 3-1 head-to-head record over Wawrinka. 2008 Rome runner-up Wawrinka beat Isner in their first clash in Tokyo in 2009 -- losing 3 straight to the American since.

Wawrinka hasn't had a great campaign in the clay court season thus far. The Swiss collected two round-of-16 achievements in Monte Carlo and Rome and a second-round showing at last week's Madrid Open. It remains to be seen whether he can rise to the occasion at the upcoming Roland Garros, where he was a champion in 2015.

Cilic's strong week continues

Croatian tennis player Marin Cilic defeated world number 10 David Goffin to progress at the Rome Masters. The number eight seed made it past the tennis player from Belgium relatively easily. The world number eight lost just seven games to the ninth-seed of Rome on his way to clinching a quarter-final spot 6-3 6-4.

Cilic hit seven aces in a contest that lasted an hour and 25 minutes.

He broke Goffin's serve three times and dropped his own serve once during the match. However, the head-to-head record still remains on the Belgian's side, with a 3-2 lead over the Croatian.

Cilic, who has yet to lose a set this week in Rome, will be meeting Isner. They are set to meet for the eighth time at the ATP level, with Croatia's Cilic having a 6-1 record over the big-serving player.

It will be a tough ask for Isner of the United States to beat Cilic on his least favorite surface -- clay.

Fognini fails to back up his win over Murray

Rising Alexander Zverev will also be featured in the quarter-final stage of the Rome Masters on Friday. The German out-gunned local Fabio Fognini in a two-set battle 6-3 6-3.

Clay court specialist Fognini was coming off of a big win over world number one Andy Murray, but could not build on that.

Zverev broke Fognini early on in both sets and eventually clinched the win. The match came to an end after an hour and 18 minutes. World number six Milos Raonic will be Zverev's next opponent in the tournament.