Stanislas Wawrinka stunned by Dominic Thiem, 20, at Madrid Open

This victory is Dominic Thiem's first over a top-20 player. (PIERRE-PHILIPPE MARCOU/AFP/Getty Images) Welcome to the big time, Dominic Thiem. The 20-year-old

This victory is Dominic Thiem's first over a top-20 player. (PIERRE-PHILIPPE MARCOU/AFP/Getty Images)

Welcome to the big time, Dominic Thiem. The 20-year-old Austrian qualifier continued his breakthrough season with an impressive 1-6, 6-2, 6-4 win over No. 3 Stanislas Wawrinka in the second round of the Madrid Open on Tuesday.

Thiem, the youngest player in the top 100 (No. 70), recovered from a quick opening-set loss to stand toe-to-toe with the Australian Open and Monte Carlo Masters champion. He served bigger -- his first serve averaged 119 mph to Wawrinka's 116 mph -- and matched the Swiss for winners off the ground. Thiem recorded his first top-20 victory and became the first 20-and-under player to defeat a top-five player in three years.

"It's my biggest win by far," Thiem said. "I couldn't really handle his pace in the beginning, but I got used to it and played unbelievable in the second and third set."

One example of Thiem's fine form in the final two sets:

Here are few things to know about Thiem:

This has been his breakout season. Thiem turned pro two years ago after a good junior career that saw him get as high as No. 2. He spent last season on the Futures and Challenger circuit before making two ATP World Tour quarterfinals, including at the Vienna Open, where he lost to Jo-Wilfried Tsonga in a third-set tiebreak. He pushed Andy Murray to three sets in Rotterdam in February, after which the reigning Wimbledon champion said of Thiem, "We'll be hearing a lot from him. Before Tuesday, Thiem's best win was a straight-set victory over No. 23 Gilles Simon in Indian Wells in March. Thiem, who started this season ranked No. 139, will continue to climb after his win against Wawrinka.

He leads the ATP this season in successful qualifying campaigns. There's been a lot of discussion this season about the merit of wild cards, which are issued at disproportionate rates to players from well-established tennis nations. Despite being an up-and-comer, Thiem has received only one wild card (Monte Carlo) in nine tournaments. However, he's successfully qualified in seven of eight tournaments, including the Australian Open and three ATP Masters 1000s, and only once (Doha) did he fail to back up his qualifying campaign with a first-round win.

Dominic Thiem credits the amount of matches and the amount of times he had to come through Qualies in 2014 as making him match tough.

— Nick Lester (@nicklester) May 6, 2014

Any player who qualifies just about EVERY WEEK (bar one, Acapulco) on the ATP Tour is the real deal!! Thiem has serious upside potential...

— Rob Koenig (@RobKoenigTennis) May 6, 2014

He has a powerful game that makes you think, Baby Stan. Armed with power from the baseline and a huge one-handed backhand, Thiem has earned comparisons to the man he beat in Madrid. Big hitting fueled Tuesday's victory, and his challenge will be to harness that power to make smart shot-making decisions and become more consistent. But it's easy to see why people are excited about his prospects. You like to see young players with weapons that will only develop over time, and Thiem has an arsenal.

He's best friends with Ernests Gulbis: The two are frequent practice partners and share a coach in Günther Bresnik. If Gulbis considers him worth his time, then he must be a pretty cool kid. Not that the influence isn't worrying at times:

He trains by carrying logs through the forest: You can read the fantastic account of his offseason here.

He writes thorough and thoughtful Facebook updates: Thiem's Facebook page is a must-follow. His status updates are reflective and earnest, bordering on personal journal entries. Here's what he wrote after beating Dmitry Tursunov in the first round of Madrid:

6:4, 6:2 against Dimitry Tursunov. Just had to save one break point.  I already played solid from the baseline for the last few weeks. And the return improved as well. But I am so happy with my serve right now. I can serve fast but can mix it up too. It has become an effective tool lately. I beat three top 100 players in three days here for the first time ever. And now I get the coolest reward ever: playing Stan Wawrinka, the number one in the ATP race. Against the best player of the year on a big court - can you imagine anything better?  Please keep your fingers crossed for me, maybe I can cause him a little trouble.  Bamos!!