After rain limited play on Wednesday, the second round was completed on Thursday in Stuttgart, including the top four seed all getting their campaigns underway. There were some surprises on day four at the Mercedes Cup, so let’s take a look back at what happened on Thursday in Stuttgart.

Results

Roger Federer was up a break at 4-3 in the first set of his match with Taylor Fritz when rain forced them to stop yesterday. When play resumed, the Swiss closed out the set, but the American teenager would not go away, forcing Federer to fight until the end, with the top seed eventually edging out a 6-4, 5-7, 6-4 victory. After dropping the opener, Fritz was all over the 17-time major champion in the second set, not allowing a single break point on his own serve and reaching break point six times, breaking Federer for the set in the 12th game. He narrowly out-chanced the Swiss again in the third, but could not convert either of his break points, while Federer converted his only chance which would be enough to seal a three-set victory.

Dominic Thiem plays a forehand during his second round win. Photo: Thomas Kienzle/AFP/Getty Images
Dominic Thiem plays a forehand during his second round win. Photo: Thomas Kienzle/AFP/Getty Images
 

Recent French Open semifinalist and third seed Dominic Thiem faced a test in the form of monster-server Sam Groth, with the Austrian narrowly edging the Aussie in a pair of tiebreaks. Groth was strong as always on serve, pounding 21 aces, winning 86 percent of his first serve points, and saving the only break point of the match. However, Thiem exposed the big-servers weakness, his poor return, and was even stronger on serve, winning more first and second serve points and not facing a break point. Both sets required tiebreaks and Thiem showed why he’s ranked in the top ten, winning them 7-3 and 7-2 to reach the quarterfinals.

Fourth seed Gilles Simon was tested in his second round match against Jan-Lennard Struff, but in the end, the Frenchman found the edge, claiming a 6-4, 4-6, 6-2 victory. Simon started strongly, only dropping six points on serve and claiming the lone break of the opening set for the early lead. Struff returned the favour in identical fashion in the second set, before Simon did it again in the third, only scoring two breaks to cruise into the quarterfinals.

Radek Stepanek hits a backhand during his upset win. Photo: Thomas Kienzle/AFP/Getty Images
Radek Stepanek hits a backhand during his upset win. Photo: Thomas Kienzle/AFP/Getty Images
 

There was a major upset in the second round on Thursday, as qualifier Radek Stepanek ousted second seed Marin Cilic in straight sets. The Czech veteran won an astounding 91 percent of his first serve points and only gave the second seed one break point, which was saved, in a 7-6(4), 7-5 victory. The 2014 US Open champion was no slouch on serve himself, winning 83 percent of his first serve points and pounding 12 aces. However, he allowed a costly late break in the second set which resulted in his defeat.

In other action, Mikhail Youzhny defeated Sergiy Stakhovsky in straight sets, while Juan Martin Del Potro continued his strong run with a routine straight-sets win over John Millman. The quarterfinals will take place tomorrow.