MELBOURNE, Australia (AP) As befitting his status as a 17-time Grand Slam champion and as an astute judge of the sport, Roger Federer's reply to a simple question about his next opponent was handled with the same aplomb as one of his stylish groundstrokes.
The player in question was Kei Nishikori, who plays Federer in a fourth-round night match Sunday at Rod Laver Arena.
''I'm a big fan of his game,'' Federer said. ''He's got one of the best backhands out there. I love how he can crush it down the line or cross-court. He's got wonderful second serve returns. He's fast on his legs. Strong in his mind. I know how tough he is as the match goes along. He finds his range and his rhythm, he's tough to stop.''
Federer said he'll need another strong service game if he's going to give Nishikori some trouble. In Federer's win over Tomas Berdych on Thursday, he didn't face a break point and he won points on 95 percent of the first serves he got into play - 39 of 41, and all 16 in the third and final set.
''This one's going to be completely different to Tomas ... there's going to be more rallies, even though the surface remains fast. I said it at the beginning of the week, it's not easy to control the ball. Today again, when you serve well, it pays dividends. I hope I can keep that up against Kei.''
Asked if Nishikori should be considered the favorite because of the No. 5 seeding (Federer is 17th after a six-month left knee injury layoff) Federer replied, smiling: ''Yeah, sure, he's the favorite. Maybe. I don't know.''
Nishikori said he watched some of the Federer-Berdych match and was impressed.
''Roger, it's a big challenge for me,'' Nishikori said. ''I'm just happy to play him because I think we needed him on the tour. Happy to see him back 100 percent.''
Here are some other featured matches Sunday:
NO PRESSURE: Top-seeded Andy Murray plays Mischa Zverev in an afternoon match at Margaret Court Arena.
Murray, a five-time Australian Open finalist, is heavily favored. The 50th-ranked Zverev, the older brother of 19-year-old rising star Alexander Zverev - who lost to Rafael Nadal in the third round - says Murray could go either way while pondering his ranking advantage.
''I don't know if it's more pressure on him or maybe it's a relief,'' Mischa Zverev said. ''If someone like Novak (Djokovic) is out of the tournament, I feel like the whole rhythm of the tournament changes a little bit, so we'll see what's going to happen.''
Zverev hopes to possibly rile the often volatile Murray.
''If he plays his best tennis, obviously I don't think I have a lot of chances, but it'll depend on the day,'' he said. ''Let's see if I can annoy him a little bit. If I'm serving well and not missing any volleys, maybe I can do some damage.''
KERBER IN CONTROL?: Defending champion Angelique Kerber plays American CoCo Vandeweghe in the match following Federer-Nishikori on Rod Laver. Kerber holds a 2-0 career edge, although the last time the two played - in Wuhan, China in 2015 - Vandeweghe retired from the match with a left ankle injury while trailing 6-1, 3-1. ''CoCo is a tough opponent ... she's serving well,'' Kerber said. ''I have to move good ... bring a lot of balls back, but also be aggressive.''
IN BRIEF: Venus Williams, who is appearing in her 73rd Grand Slam main draw - a record for the Open era - plays Mona Barthel in an afternoon match. U.S. Open champion Stan Wawrinka continues his quest for titles in consecutive Grand Slams - and his fourth major overall - when he plays Andreas Seppi. French Open champion Garbine Muguruza plays Sorana Cirstea.
Associated Press writer Justin Bergman contributed to this story.