Milos Raonic's Australian Open has ended at the hands of Rafael Nadal in the quarterfinals.

Raonic lost in straight sets to the 14-time Grand Slam champion 6-4, 7-6 (7), 6-4. The win puts Nadal back in the semifinals of a major tournament for the first time since winning the 2014 French Open. 

The ninth-seeded Nadal held the advantage heading into the match, having won six of eight previous contests against Raonic.

But many wondered if this was Raonic's year after top-ranked Murray and No. 2 Novak Djokovic were upset in earlier rounds.

It has been a struggle from the beginning, however, as Raonic came down with a cold early in the tournament and was bed-ridden for a day. His timing seemed slightly off against Roberto Bautista Agut in the round of 16, when he racked up 55 unforced errors and even uncharacteristically hurled his racket to the court midway through the third set.

He appeared to be feeling better by Wednesday, but then had a recurrence an adductor injury in the loss to Nadal.

"These last two and half weeks have been quite difficult, just trying to manage everything," he said. "First, dealing with the physical aspect, then getting myself quite ready, I thought, making the most of that. Then dealing with the health aspect and now with this."

'He played better than I did' 

Raonic, 26, said he came into Melbourne nursing his thigh muscle after injuring it earlier this month in Brisbane.

"I got it to pretty good shape," he said. "We still had to monitor it and then today I hurt another aspect of it."

He required treatment on the leg in the second set Wednesday.

"I hope it's nothing too serious," added Raonic, who has struggled with adductor problems in the past.

Raonic defeated Nadal in their last meeting, which came at the same tournament in Brisbane where Raonic said he tweaked his adductor.

This time, Raonic said, "he played better than I did."

The 30-year-old Nadal saved six set points in the second set, including two in the 13-minute tiebreaker.

"There were some opportunities in the second set, other than that, there wasn't much for me to hold onto," Raonic said. "I thought he did some things well... He did something a little bit different than he normally does.

"I just wasn't able to push him back behind the baseline like I was a few weeks ago."

'I had a lot of doubts' 

Raonic has come close to a Grand Slam title several times only to see it slip away. He said he didn't want to ponder the fact that his goals have often been derailed by bad luck.

"I don't want to depress myself thinking about that too much right now," he said.

Raonic, the third-seed from Thornhill, Ont., was trying to repeat his best showing at the Grand Slam tournament by reaching the semifinals for a second straight year. He lost to Andy Murray in the 2016 semis.

Raonic was the highest remaining seed in the quarter-finals after top-seed Murray lost to Germany's Mischa Zverev in the fourth round and second-seed Novak Djokovic was upset in the second round by Denis Isotomin.​

Nadal returns to the final four at a Grand Slam tournament for the first time since winning the 2014 French Open. His return ensures there will be three players over 30-years-old in the men's semifinals, equalling the Open era mark set at Roland Garros in 1968.

Nadal will play Grigor Dimitrov on Friday, the day after 35-year-old Roger Federer takes on 31-year-old Stan Wawrinka in an all-Swiss semifinal.

"Even when I was winning a lot I had doubts, you can imagine I had more when I had injuries," Nadal said. "I think I had a great career, but at the same time I had a lot of tough moments. That makes me enjoy even more the good moments I'm having today."​

Serena through to semis

Serena Williams reached her 10th consecutive Grand Slam semifinal, and kept her bid alive for a record 23rd major title, with a 6-2, 6-3 win over Johanna Konta on Wednesday.

Her opponent in the semifinals, Mirjana Lucic-Baroni, who beat fifth-seeded Karolina Pliskova 6-4, 3-6, 6-4, had a much longer wait to get back to this stage at a major — nearly 18 years.

It's the second time in the last two years that three women in their 30s have reached the semifinals at a major: Venus Williams, 36, Serena Williams, 35, and Lucic-Baroni, 34. Serena also reached the semifinals at the 2015 U.S. Open, alongside 30-somethings Flavia Pennetta and Roberta Vinci.

"Thirty is the new 10," Williams said after her match. "No matter what happens, somebody 34 or older will be in the final."

Williams struggles with serve

The second-seeded Williams was tested by Konta in the second set when the British player broke her to go up 2-1. But Williams broke back at love to level the score at 3-all and saved another break point in her next service game before closing out the match.

Williams finished with 10 aces, but only connected on 45 per cent of her first serves overall.

"The main focus is actually my serve even though I missed a lot today," she said. "I got a little frustrated, but then I just told myself, 'Serena, stop complaining. Don't be Baby Rena out here."'

Once a prodigy

Lucic-Baroni advanced to the last four at a major for the first time since her run to the Wimbledon semifinals in 1999 at the age of 17.

The last time she made it this far, Lucic-Baroni also had to face a woman in the semifinals with 22 majors — Steffi Graf. Graf won that match, but fell short in her bid to win her 23rd major title against Lindsay Davenport.

Lucic-Baroni is surprised she is getting another chance at this stage of her career.

She was once considered a prodigy with as much promise as the Williams sisters. She won the first tournament she entered as a 15-year-old in 1997 and several months later captured the 1998 Australian Open doubles title with Martina Hingis.

After her run to the Wimbledon semifinals the following year, however, Lucic-Baroni's career was sidetracked by personal issues and financial problems. She was largely out of the sport for several years before launching a comeback in the late 2000s.

"I know this means a lot to every player to reach the semifinals, but to me, this is just overwhelming," she said, in tears, after the match. "This has truly made my life and everything bad that happened, it has made it OK."

The 79th-ranked Lucic-Baroni is the third-lowest-ranked player to reach the semifinals of the Australian Open after Justine Henin (unranked, 2010), Claudia Porwick (No. 81, 1990) and Williams (No. 81, 2007).