Check out some of the headlines and results from the top tournaments around the world on Thursday that you may have missed while you were sleeping.
Roger Federer outlasts John Millman in opener in Brisbane.
Federer went down early in his second round match against Australian wild-card entry Millman on Thursday. In just over two hours, Federer came back to beat Millman 4-6, 6-4, 6-3 and earn a spot in the next round.
"It's the first match of the season, so you never know what to expect," Federer said. "I was sweating like crazy. I was just happy to win."
Federer will face another Australian wildcard, James Duckworth, in the next round. Third-seeded Milos Raonic had 17 aces in his 6-3, 6-4 win over Mikhail Kukushkin on Thursday. He'll play Sam Groth in the quarterfinals.
Ivo Karlovic stuns Novak Djokovic in Doha.
The big-serving Croat fired down 21 aces in windy conditions to beat Djokovic 6-7 (2), 7-6 (6), 6-4 and advance to the Qatar Open semifinals. It's tough to beat Karlovic on any day when he's serving about 70 percent. Karlovic will face No. 4 seed David Ferrer. Tomas Berdych and Andreas Seppi will contest in the other semifinal.
Maria Sharapova and Ana Ivanovic power through in Brisbane.
No WTA player has been as impressive as Sharapova to start the season. The Russian look strong in her first two matches and earned a win over Carla Suarez Navarro 6-1, 6-3 on Thursday to advance to the semifinals at the Brisbane International. No. 2 seed Ana Ivanovic had a much tougher time and it took her nearly two hours to beat Kaia Kanepi 4-6, 6-4, 6-3.
Sharapova will face Elina Svitolina in the semifinals -- the 20-year-old Ukrainian stunned No. 3 seed Angelique Kerber 4-6, 7-5, 6-3 on Thursday. Ivanovic pulled out of her doubles match with Kerber on Thursday and face Varvara Lepchenko on Friday. Lepchenko has had a great week in Brisbane, with wins over Sam Stosur, Madison Keys in her previous matches and a 7-5, 7-5 win over lucky loser Alla Kudryavtseva on Thursday.
Caroline Wozniacki and Venus Williams advance to the Auckland semifinals.
The top two remaining seeds advanced with relative ease at the ASB Classic. Wozniacki beat the erratic Julia Goerges 6-4, 6-4 and Venus evened her head-to-head with Elena Vesnina to 2-2 after a 6-2, 6-4 win. Wozniacki will face Barbora Zahlavova Strycova in the semifinals. The Czech ousted CoCo Vandeweghe 6-4, 7-5, battling back from a 2-5 deficit in the second set.
The other semifinal is an all-American duel between Venus and Lauren Davis, who followed up her win over Sloane Stephens with a three-set victory over Urzsula Radwanska.
Simona Halep and Petra Kvitova on track for a clash.
The top two seeds advanced to the Shenzhen Open semifinals in straight sets. Halep will play Zheng Saisai and Kvitova will play Timea Bacsinszky.
U.S. keep Hopman Cup title hopes alive.
Serena Williams overcame a shaky second set to beat Lucie Safarova 6-3, 6-7 (1), 7-6 (6) and then Isner then defeated Adam Pavlasek 7-6 (4), 6-2 at Perth Arena on Thursday to set up a mixed doubles match that would earn the winner a spot in the final. Serena and Isner finished out their 3-0 sweep over the Czechs with a 6-3, 6-3 victory in the mixed doubles match give Team USA a ticket to Saturday's final. After the match, Isner was asked if he and Serena were the best mixed doubles team ever: "I don't know about that. We're pretty good. Serena is arguably the best player of all time, that doesn't hurt."
Photo of the day
Video of the day
Mirjana Cicak is already in fine form:
Matches to watch
Brisbane: Federer vs. Duckworth, Bernard Tomic vs. Kei Nishikori, Sharapova vs. Svitolina, Ivanovic vs. Lepchenko
Auckland: Wozniacki vs. Strycova, Venus Williams vs. Davis
Shenzhen: Kvitova vs. Bacsinszky
Hopman Cup: France vs. Poland
Tweets of the day
This post will be updated.