The Latest: Federer wishes Nadal speedy recovery from injury

Roger Federer says he wished Rafael Nadal well after the Spaniard retired from his quarterfinal match against Marin Cilic with a leg injury.

Federer said after his quarterfinal win over Tomas Berdych at Rod Laver Arena that he sent a text message to Nadal before he went to sleep last night, adding, "I'm happy the news is not terrible. It's not nice to see fellow rival and friend go out like this."

Nadal had an MRI on his leg on Wednesday morning and said the injury to his leg is not too serious and he should only be out for three weeks.

Federer, who beat Nadal in last year's final at Melbourne Park, also commented on his rival's new look for this year's Australian Open - a sleeveless shirt similar to the one Nadal used to wear in his teenage years.

Federer joked that he couldn't pull off the look himself, telling Jim Courier in his on-court interview, "That's not going to happen. ... My arms are not like his arms. It's pretty simple."

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Roger Federer has swept aside Tomas Berdych 7-6 (1), 6-3, 6-4 to reach his 14th semifinal at the Australian Open.

The 36-year-old Federer also became the oldest man to reach the semifinals at Melbourne Park since Ken Rosewall did it in 1977 at age 42 and the oldest man to advance to the final four at any major since Jimmy Connors at the 1991 U.S. Open at age 39.

Federer, the No. 2 seed and defending champion, has now beaten Berdych for the 20th time in his career. He hasn't lost to the Czech veteran since Dubai in 2013.

Federer, who hasn't dropped a set yet in the tournament, next faces South Korea's Hyeon Chung for a spot in the final.

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Lleyton Hewitt's return to the Australian Open has come to an end, albeit much later than he was expecting.

Hewitt came out of retirement for this year's tournament to play men's doubles with his former Davis Cup teammate, Sam Groth, who is playing his final tournament.

The pair won three matches at Melbourne Park, including an upset over the No. 3-seeded team of Jean-Julien Rojer and Horia Tecau, but their luck ran out in the quarterfinals on Wednesday as they fell to Colombia's Juan Sebastian Cabal and Robert Farah 6-4, 7-5.

Afterward, two-time major winner Hewitt said "playing in front of great crowds on big home courts like this is what you really miss" in retirement. The 36-year-old Hewitt played his last singles match at the Australian Open in 2016 and is now Australia's Davis Cup captain.

The 30-year-old Groth's career highlight was a semifinal finish in doubles at the French Open and two doubles quarterfinals at the Australian Open.

Hewitt said of his teammate, "I loved playing Davis Cup with this fella. He wore his heart on his sleeve ... and for me to come out and play alongside him in his last event was pretty special."

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Top-seeded Simona Halep recovered from an early service break and won nine straight games en route to a 6-3, 6-2 victory over No. 6-seeded Karolina Pliskova to reach the Australian Open semifinals for the first time.

Halep, playing as the No. 1 seed for the first time in a Grand Slam tournament and seeking her first major title, will face 2016 champion Angelique Kerber in the last four.

Halep has overcome her challenges so far at Melbourne Park. She badly twisted her ankle in an earlier round, and had to fend off triple match point before beating American Lauren Davis 4-6, 6-4, 15-13 in the third round. In terms of games, it was the equal-longest women's singles match at the Australian Open. In her first four rounds, Halep spent 8 hours and 44 minutes on court.

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Madison Keys is upbeat in defeat, saying she still believes a big win is coming for her at a Grand Slam.

Keys said after her loss to Angelique Kerber in the quarterfinals of the Australian Open that she's "not going to walk away from this tournament and think it was terrible because I had one bad match."

Keys has described being "devastated" following her straight-sets loss to Sloane Stephens in last year's U.S. Open final, but said she was feeling differently after falling to Kerber in similarly lopsided fashion, 6-1, 6-2.

She said, "I definitely think I have taken a lot of steps in the right direction and feel good about my game and feel like I'm thinking a lot clearer out there. I think it's just going to take a little bit of time."

Keys, who missed last year's Australian Open after undergoing wrist surgery, had been playing well in her first four rounds at Melbourne Park. She had dropped just 19 games - the fewest among the eight women's quarterfinalists.

Asked why she was taking this defeat in stride, she replied, "I'm evolving. I'm growing. I think I'm handling myself pretty well right now."

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Hyeon Chung's historic run through the Australian Open draw is continuing.

Chung beat Tennys Sandgren 6-4, 7-6 (5), 6-3 in the quarterfinals on Wednesday to become the first Korean player ever to reach the semifinals of a Grand Slam. He finally closed out a lengthy final game by converting on his sixth match point.

At 21 years old, Chung is also the youngest man to reach the semifinals of a Grand Slam since Marin Cilic made it this far at the Australian Open in 2010.

The No. 58-ranked South Korean player upset No. 4-seeded Alexander Zverev in the third round and six-time champion Novak Djokovic in the fourth. He'll next face the winner of the match between Roger Federer and Tomas Berdych on Wednesday night.

Sandgren had only won two ATP Tour-level matches in his career before his run to the quarterfinals at Melbourne Park. He upset two top-10 players in the past week - Stan Wawrinka and Dominic Thiem.

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Rafael Nadal says he had an MRI conducted on Wednesday morning and it confirmed he has a muscle injury in his upper right leg.

The top-ranked Nadal retired from his quarterfinal match against Marin Cilic on Tuesday night while trailing 0-2 in the fifth set. It was only the second time in his career he's retired during a Grand Slam match.

He says he expects the injury to heal in three weeks and he'll return to the tour in Acapulco, Mexico, at the end of February.

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False alarm: Calls over the stadium speakers for the crowd to evacuate caused a delay to the start the Australian Open men's quarterfinal match between Hyeon Chung and Tennys Sandgren on Rod Laver Arena.

Some of the fans headed toward the exits, but the players remained behind the baselines as chair umpire James Keothavong contacted stadium staff to work out if it was a false alarm.

After a few minutes, Keothavong announced: "Ladies and gentlemen. Thanks for your patience. False alarm."

The match got underway with Sandgren holding serve in the first game.

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Angelique Kerber had a 6-1 win-loss record against Madison Keys coming into their quarterfinal match at Melbourne Park, but she didn't expect an easy match.

She said afterward, "It's always tough to play against Madison. She's hitting the ball so hard, the serve is also really fast, so I was just trying from the beginning, like I played the whole week, just going out there, playing my game and enjoying it."

Kerber said after winning the first set handily, she tried not to lose her focus.

"You know that she's coming back, you know Madison. She's fighting until the last point."

Keys got her only break of the match at 1-3 in the second set, but Kerber was able to break back in the next game and then again to close out the match.

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Angelique Kerber is through to the Australian Open semifinals after a commanding 6-1, 6-2 win over Madison Keys.

For Kerber, who kicked off her career-best season with her run to the title here two years ago, it was her first quarterfinal at a major since her victory in the 2016 U.S. Open.

The momentum was all one-way until Keys broke for the first time in the fifth game of the second set, but Kerber recovered quickly to finish off in 51 minutes.

Kerber has been the only major winner still in the women's draw since her third-round win over Maria Sharapova.

Keys reached the U.S. Open final last September but lost in straight sets to Sloane Stephens.

Kerber's semifinal opponent will be decided later Wednesday in a quarterfinal match between top-ranked Simona Halep and No. 6 Karolina Pliskova.