Japan’s Kei Nishikori survived a scare on Monday to advance to the third round of the Rio Olympics. Aussie John Millman was up a break in both sets, but the fourth seed came back to win 7-6(4), 6-4.

Millman, No. 74 in the Emirates ATP Rankings, served for the first set at 5-4 but was broken. He also led 4/0 in the tie-break, but Nishikori roared back to win seven straight points and take the first set. The 27-year-old Millman also led 4-3 in the second set, but lost his next two service games.

Nishikori will next face Slovakia’s Andrej Martin, who received a walkover when German Philipp Kohlschreiber withdrew because of a right foot injury.

Juan Martin del Potro backed up the biggest upset of the Olympics with another strong performance. The Argentine moved into the third round with a 6-3, 1-6, 6-3 win against Portugal’s Joao Sousa, No. 36 in the Emirates ATP Rankings. Del Potro struck 13 aces and lost only two points on his serve (20/22) in the third set. The 27 year old also bullied play with his forehand, hitting 16 forehand winners compared to one from his backhand side.

The 6’6” right-hander, who has struggled with wrist injuries over the past few years, will look to reach the quarter-finals in Rio when he faces Japan’s Taro Daniel, who swept #NextGen player Kyle Edmund of Great Britain, 6-4, 7-5. Del Potro started his Olympics with a 7-6(4), 7-6(2) victory against World No. 1 Novak Djokovic.

Luxembourg’s Gilles Muller hit 14 aces to prevail over fifth seed Jo-Wilfried Tsonga 6-4, 6-3. It’s the latest big win for Muller, who’s reached two of his five career ATP World Tour finals this season.

Muller, who carried the flag for his home Luxembourg in the opening ceremony, will try to continue his best Olympic run when he faces 10th seed Roberto Bautista Agut in the third round. Muller fell in the second round in London in 2012. Bautista Agut denied Italian Paolo Lorenzi 7-6(2), 6-2 in 89 minutes.

Ninth seed Marin Cilic swept his way into the third round, dispatching Moldova’s Radu Albot 6-3, 6-4. The top Croatian broke Albot four times and will next face Frenchman Gael Monfils, who upset the home crowd by beating Brazilian Rogerio Dutra Silva 6-2, 6-4 in 73 minutes. Monfils is coming off his first ATP World Tour 500 title at the Citi Open in Washington and a runner-up finish at the Rogers Cup (l. to Djokovic), an ATP World Tour Masters 1000 in Toronto.

Read More: Monfils Outlasts Karlovic For D.C. Crown

DOUBLES

Rafael Nadal won for the second day in a row in Rio, pairing with Marc Lopez to beat del Potro and Maximo Gonzalez 6-3, 5-7, 6-2. Nadal won his first-round singles match on Monday. The Spaniards will next face Austrians Oliver Marach and Alexander Peya, who outlasted Americans Rajeev Ram and Brian Baker 6-4, 6-7(2), 6-3.

Home favourites Marcelo Melo and Bruno Soares swept past Serbians Novak Djokovic and Nenad Zimonjic 6-4, 6-4. The third seeds will face the fifth seeds, Romanians Florin Mergea and Horia Tecau, who beat Mexicans Santiago Gonzalez and Miguel Angel Reyes-Varela 6-3, 7-6(9).

Americans Steve Johnson and Jack Sock defeated the Colombian team of Juan Sebastian Cabal and Robert Farah 6-4, 7-6(1). Johnson/Sock will face Bautista Agut and David Ferrer, who beat Lukasz Kubot and Marcin Matkowski of Poland 6-3, 7-6(5).

Tomas Berdych revealed on Monday that he will begin to work with Goran Ivanisevic at next week’s Western & Southern Open in Cincinnati.

“I am delighted to announce a new addition to my team,” Berdych wrote on his official Twitter account. “Two months ago, I started working with Luka Kutanjac and I feel that, since then, my game has [improved] and my form has been going in the right direction. In order to further improve, I have decided to add Goran Ivanisevic to the team already in Cincinnati.

“I feel that Goran, with his playing and coaching experience, as well as his energy, is a perfect addition to the team. [I’m] feeling excited about new challenges.”

Ivanisevic parted company with fellow Croatian Marin Cilic, the 2014 US Open champion, on 21 June after a three-year partnership. Former World No. 2 Ivanisevic, one of the biggest servers of the Open Era, captured the 2001 Wimbledon title as a wild card entry.

Berdych, 30, is currently No. 8 in the Emirates ATP Rankings. He has a 12-17 record in tour-level finals.