Melbourne: Roger Federer's rediscovered form will be put to the test when he takes on Japan's Kei Nishikori for a place in the Australian Open quarter-finals on Sunday.
Federer's return from a six-month injury break clicked into gear in round three, when he thrashed Tomas Berdych in just 90 minutes in a performance of vintage quality.
But the 35-year-old may have to work harder against the energetic Nishikori, who has won two of their six matches and has started the year well, reaching the Sydney final.
Fifth seed Nishikori is targeting his first major title, while Federer is looking for his 18th. Both players' chances have increased with the shock elimination of Novak Djokovic.
Seventeenth seed Federer, when asked if Nishikori was the favourite due to his higher ranking, smiled: "Yeah, sure, he's the favourite. Maybe.
"I don't know. It doesn't matter. I still have to play Kei. If he's the favourite, I'm the favourite, I don't know. But he's definitely played better and more tennis in recent months.
"But then again, it's a new season. We'll see what happens. But I'm a big fan of his game. He's got one of the best backhands out there."
Andy Murray has also started convincingly and the world number one will be the strong favourite against Germany's 50th-ranked Mischa Zverev.
Murray has reached the quarter-finals every year since 2010, and he hasn't lost to anyone in Melbourne with a ranking as low as Zverev's since Juan Ignacio Chela in 2006.
The five-time finalist is well-acquainted with Zverev, his contemporary at 29 and an old sparring partner dating back to their junior days.
"He plays a very different game style to most of the guys now. He's serve-volleying, coming forward as much as possible, not with the most powerful game," Murray said.
"He doesn't serve, like, 220 kilometers (137 miles) an hour. He serves 185s, 190s, but places it well. People say you can't play that way any more and be successful, but he's done that the last few months."
If Murray and surprise package Dan Evans both go through, Britain will have two men in the Australian Open quarter-finals for the first time in 30 years.
Evans, who has knocked out seventh-ranked Marin Cilic and home hope Bernard Tomic in the last two rounds, goes into what looks like an entertaining clash with Jo-Wilfried Tsonga.
In the women's draw, top seed and defending champion Angelique Kerber takes on America's Coco Vandeweghe, and French Open champion Garbine Muguruza plays Sorana Cirstea.
Venus Williams is favourite against German qualifier Mona Barthel and veteran Svetlana Kuznetsova faces fellow Russian Anastasia Pavlyuchenkova.
Updated Date: Jan 22, 2017 06:37 AM