Melbourne, Australia (SportsNetwork.com) - Four-time champion Novak Djokovic handled Milos Raonic, while Stan Wawrinka kept his hopes of a repeat Australian Open title alive by besting fifth-seeded Kei Nishikori in straight sets on Wednesday.

The world No. 1 Djokovic dismissed the eighth-seeded Canadian star Raonic 7-6 (7-5), 6-4, 6-2, while the fourth-seeded Wawrinka fired 20 aces and was broken just once in a 6-3, 6-4, 7-6 (8-6) quarterfinal victory over the U.S. Open runner-up Nishikori at Rod Laver Arena.

The 27-year-old Djokovic is bidding to become the second man in history to win the Australian Open for the fifth time, joining Aussie great Roy Emerson. The Belgrade native won his first major title in Melbourne in 2008 and followed with three successive victories in 2011-13. He has a 48-6 match record at Melbourne Park.

Djokovic still has yet to drop a set in his ruthless run at this 2015 fortnight. He is through to his 25th Grand Slam semifinal, one behind Andre Agassi for the fourth most in the Open Era.

Djokovic improved to 5-0 against Raonic, as he doused the Canadian in two hours. The Serb was not at his best in the first set, not quite finding his timing under the lights at Laver. But a costly forehand unforced error from Raonic at 5-6 in the tiebreak -- having just saved two set points -- gifted the Serb the opener.

From there, Djokovic was clinical. He lost just two points on serve in each of the second and third sets, while breaking Raonic three times in total.

"It was a close first set, but I thought I had more chances in the first set than him," said Djokovic. "Managed to stay tough in the right moments and win the crucial first set. Obviously winning it in a tiebreak and making the break of serve first game of the second set was definitely huge really for me. I could start swinging through a little bit more, be more aggressive into the court. After that first game of the second set I played a great match."

The 24-year-old Raonic was looking to become the first Canadian in history to reach the Aussie Open semis. The Toronto resident reached his first Grand Slam semi last year at Wimbledon, losing to Roger Federer.

"I just think [the first set] gave him a bit more belief," said Raonic. "I wish I would have served better in certain moments, but I didn't lose because of my serve. He just didn't allow me to organize my game. Even when he was returning well, by the end of the match he was doing a good job of playing deep and never allowing me to go forward. Obviously if you watch the footage, he was pretty much on the baseline the whole time and I was further back."

The reigning Wimbledon champion Djokovic is seeking an eighth Grand Slam title.

A five-set thriller was played between Wawrinka and Nishikori at last year's U.S. Open, and it was Nishikori who survived a 4-hour, 15-minute marathon.

The evenly-matched opponents were on the court for less than half that on Wednesday.

The defending champ Wawrinka dominated the first set and did not face a break point until he was serving out the second ahead 5-4. Nishikori had three chances at pulling even, but Wawrinka's overpowering serve closed it out.

Nishikori finally earned a break early in the third, but Wawrinka countered with one of his own at love. Three aces early in the tiebreak helped Wawrinka jump out to a healthy 6-1 lead.

After staving off five match points, Nishikori hit a drop shot that fell into the net, and Wawrinka finished him off with another big ace.

On Friday, fans will be hoping for another epic when Djokovic faces Wawrinka for the third year in a row at Melbourne Park. Two years ago, Djokovic denied Wawrinka 12-10 in the fifth set of a fourth-round clash, but last year the Swiss got his revenge with a 9-7 fifth-set victory in the quarterfinals.

"I take a lot of confidence [into the match]," said Djokovic. "I try to carry that in every next match, next challenge. Obviously I'm going to play Stan, who is the defending champion here. We played five-set matches at the 2013 and '14 Australian Opens. I'm going to be ready for a fight. But knowing that I have raised the level of performance tonight, and probably playing the best match of the tournament so far is affecting my confidence in a positive way. Hopefully I can carry that into next one."

Djokovic is 16-3 lifetime against Wawrinka, including a 3-1 record at the majors.

The first men's semifinal will be staged on Thursday when sixth-seeded Andy Murray takes on seventh-seeded Tomas Berdych. The big Czech is 6-4 lifetime against Murray, including 1-1 at the Slams.

Murray is a two-time Grand Slam champion and three-time Aussie Open runner-up, while Berdych is a former Wimbledon finalist.