Japanese tennis stars Kei Nishikori and Go Soeda are ATP Tour opponents one week, and Olympic teammates the next. Nishikori and Soeda posted second-round victories to set up an all-Japanese quarter-final with their post-midnight wins at the Atlanta Open tournament on Wednesday. It marks the first time the pair will square off against each other as professionals. Soeda turned pro in 2003 and Nishikori turned pro four years later. They face off in the next round on Friday and then will head to the London Games as soon as the Atlanta hardcourt tournament is over. The third-seeded Nishikori outlasted Ricardas Berankis 6-4, 6-7 (7/9), 6-4, while the eighth-seeded Soeda routed Russian Igor Kunitsyn, 6-1, 7-5 on a day when the matches at Atlantic Station were postponed five hours because of bad weather. World number 19 Nishikori didn't finish his match until close to 2:00 am Atlanta time (0600 GMT) after he failed to win a second set tie-breaker. Nishikori has advanced to the quarter-finals in three of his previous four tournaments. This is the first quarter-final for Soeda since the opening week of the season when he made it to the Chennai semis. In other matches, fourth-seeded American Andy Roddick downed Frenchman Nicolas Mahut 7-6 (7/4), 6-3. Roddick will play American compatriot Michael Russell in the quarter-finals after Russell defeated fifth-seeded South African Kevin Anderson, 6-7 (5/7), 6-4, 6-4. The 29-year-old Roddick improved to a 15-12 this season. He won his first title in 2001 at Atlanta when it was a claycourt tournament. Defending champ Mardy Fish and John Isner, who is fresh off his Newport title, will play their first matches on Thursday.