The funky shorts have gone and, it seems, taken some of Stan Wawrinka's mojo with them. To defend his French Open title, he knows he will need to get it back.

Following a five-set win in the first round, Wawrinka again wasn't convincing in the second round on Wednesday at Roland Garros, with a 7-6 (7), 6-3, 6-4 victory over Taro Daniel of Japan that wasn't all that straightforward.

Most notable were the break points the third-seeded Swiss player failed to convert against a player 89 spots below him in the rankings and who stalled in the first round last year, when Wawrinka rode his sublime back-hand to the final and won in his now infamous shorts against Novak Djokovic.

Wawrinka had 17 opportunities to break the Japanese right-hander, and converted only four of them.

"I created a lot of chances. I can't remember how many break points I had, but far too many if you look at what I did with them. The most important is to win, even more in three sets," Wawrinka said. "Hopefully I will play better and better to go as far as possible. Today there were many ups and downs, but I have my tennis and I'm ready to step it up."

Fifth-seeded Kei Nishikori is already in gear. The 2014 U.S. Open finalist broke Andrey Kuznetsov of Russia six times and saved seven break points in a 6-3, 6-3, 6-3 win.

Nishikori has spent less than four hours in two straight-set wins on the tiring red-clay courts to advance to the third round; Wawrinka has accumulated more than five hours.

Another Japanese player also is impressing. Still 18 and playing in only her second major tournament, Naomi Osaka also has yet to drop a set. After beating 32nd-seeded Jelena Ostapenko in the first round, she advanced to the third round by beating Mirjana Lucic-Baroni 6-3, 6-3.

Osaka also reached the third round in her first Grand Slam tournament, this year's Australian Open. She next plays 2014 French Open finalist Simona Halep. The sixth-seeded Romanian rallied from 4-1 down in the first set to beat Zarina Diyas 7-6 (5), 6-2.