BRISBANE, Australia (AP) Roger Federer overcame a lingering sickness to hold off Grigor Dimitrov 6-4, 6-7 (4), 6-4 on Friday and take his title defense into the semifinals at the Brisbane International.
Another former winner, the unseeded Victoria Azarenka, moved into the women's final by seeing off U.S. qualifier Samantha Crawford 6-0, 6-3.
After the men's semifinals on Saturday, the women's final will feature two-time Australian Open champion Azarenka against No. 4-seeded Angelique Kerber, who beat Carla Suarez Navarro 6-2, 6-3.
Azarenka won Brisbane in 2009, and hasn't won any title since 2013. After two seasons interrupted by injuries, she's regaining form while many of the leading women are dealing with injuries in the run-up to the Australian Open which starts in 10 days.
''I'm feeling pretty good right now,'' she said, ''I'm not saying anything besides that.''
Federer is approaching the tournament from a different angle. He delayed his opening match at the Australian Open warmup until the fifth day because of a flu-like illness, and was playing Dimitrov in the quarterfinals on less than 24 hours rest.
His serve in the first set was almost flawless, dropping just two points, and he appeared to be on course with break-point chances for another straight-set victory over the young Bulgarian - sometimes likened to him because of their similar styles - before Dimitrov rallied.
After wasting a chance to serve out the second set in a nervous 10th game, Dimitrov dominated the tiebreaker and forced a decider.
Federer, after showing signs of fatigue in the second, took a quick break before the third, and then went on a roll to set up three match points in the ninth game. Again, Dimitrov rallied, winning five consecutive points and forcing Federer to serve it out - which the 17-time major winner duly did.
''I'm not going to tell you too much, but it was tough in a way,'' Federer said of his illness. ''Body is not quite ready, so it's good to get through it without any issues.''
By holding off Dimitrov, who is 10 years his junior, Federer set up a meeting with 22-year-old Dominic Thiem, the youngest player in the top 20.
Thiem beat third-seeded Marin Cilic 2-6, 7-6 (4), 6-4 and said he was hoping to play Federer.
''It's for every young player an amazing experience to play with probably the greatest of all time,'' Thiem said. ''You can learn so many things from him.''
The other semifinal will feature 2015 finalist Milos Raonic a 6-4, 6-4 winner over No. 78-ranked Lucas Pouille, against Bernard Tomic.
Tomic ended 2014 U.S. Open finalist Kei Nishikori's streak of three straight semifinal appearances at Brisbane with a 6-3, 1-6, 6-3 win, his first over a top-10 player on home soil.
In Auckland, New Zealand, Julia Goerges reached her sixth WTA final and her first in four years when she beat qualifier Tamira Paszek 6-4, 6-2 in the ASB Classic semifinals.
Sloane Stephens was leading 5-2 in the first set of the other semifinal against third-seeded Caroline Wozniacki when rain halted play, forcing it to be postponed to Saturday.
At the Hopman Cup in Perth, Australia Green sealed its spot in the final against Ukraine by defeating France 2-1.
Nick Kyrgios gave the home team the lead when he beat Kenny De Schepper 6-4, 6-4, Caroline Garcia leveled for France with a 6-4, 7-6 (7) win over Daria Gavrilova, and the Australian pair won the mixed doubles decider 6-4, 2-6, 11-9.
In the Hopman Cup's 27-year history, host Australia has won it only once, in 1999.
''It's an event that's been held for a long, long time - before I was even born,'' the 20-year-old Kyrgios said. ''It's pretty special. Me and Dasha, we grew up together in juniors. Hopefully we can bring it home.''
Also, Andy Murray and Heather Watson beat the Germany team of Alexander Zverev and Sabine Lisicki 3-0 for Britain.