Australian Open 2016: Serena beats Sharapova - Djokovic & Federer through

Williams is closing in on a seventh Australian Open title

Serena Williams beat Maria Sharapova for the 18th time in a row to reach the Australian Open semi-finals.

The defending champion, seeded number one and chasing a 22nd Grand Slam title, saw off fifth seed Sharapova 6-4 6-1 at Melbourne Park.

The world number one, who has not lost to Sharapova in 12 years, now faces fourth seed Agnieszka Radwanska.

In the men's draw, Roger Federer and Novak Djokovic will meet in the semi-finals after straight-set victories.

Federer, a 17-time Grand Slam champion who has won the tournament four times, beat Tomas Berdych 7-6 (7-4) 6-2 6-4, while top seed and defending champion Djokovic saw off Japan's Kei Nishikori 6-3 6-2 6-4.

Williams extends dominance over Sharapova

Sharapova made it a real contest for almost an hour but eventually buckled under the American's power.

Williams, 34, appeared to struggle with her ball toss in the morning sunshine on Rod Laver Arena as she fell 2-0 down.

Williams needed attention from the tournament doctor at the end of the first set

The intensity ratcheted up as the set progressed, with both players repeatedly yelling "Come on!" as they tried to grab the initiative.

Sharapova, 28, held on valiantly in an eight-minute game to claw her way back to 4-4, but the pressure told in game 10 and Williams clinched the set at the fourth opportunity with a volley.

The world number one called for the doctor at the changeover but powered on stronger than ever in the second set, making it 12 games out of 15 as she sealed victory after one hour and 32 minutes.

"It was super intense," said Williams. "She's an incredibly intense and focused player who was world number one.

"When you're playing someone so great you have to come out with a lot of fire and intensity."

Sharapova was equally effusive about Williams. "She's at a different level. She makes you work. That's inspiring."

Radwanska earlier beat Spanish 10th seed Carla Suarez Navarro 6-1 6-3 to reach her second Melbourne semi-final in three years.

Federer reaches 12th Melbourne semi-final

Federer had lost his previous two matches against Berdych at Grand Slams

Federer had been beaten by Berdych in their past two meetings at Grand Slams, but had won their past four matches.

The Swiss fell behind early in the first and third sets but hit back immediately both times and was dominant for the most part on serve.

The 34-year-old then made a fast start to the opening-set tie-break and was in control from then on, breaking twice in the second set and making the decisive move at 4-4 in the third.

"Tomas has caused me a lot of problems over the years, but it's been a pleasure playing against him," said Federer.

"He's the type of player who makes you better."

Djokovic, chasing a sixth Australian Open title, lost just nine games as he eased past Japan's Nishikori.

The world number seven beat Djokovic in the US Open semi-finals in 2014 but he failed to make the same impact in Melbourne.

Novak Djokovic made 28 unforced errors against Kei Nishikori - compared to 100 against Gilles Simon.

Inconsistency with his returns and a niggling leg problem saw Nishikori lose his serve six times overall and Djokovic wrapped up the victory in two hours and seven minutes.

After the match, the Serb was asked about his 45th meeting with Federer, saying: "We keep playing each other in nearly every big tournament.

"It's always a big challenge. You don't need to spend words on his achievements - he is a great champion and someone I have a lot of respect for. It will be a great match."

Murray marches on in doubles

Britain's Jamie Murray reached the semi-finals of the men's doubles with new Brazilian partner Bruno Soares.

They beat 13th seeds Raven Klaasen and Rajeev Ram, conquerors of six-times champions the Bryan brothers, 6-7 (3) 6-4 7-6 (3).

Murray, the older brother of Andy, and Soares face French duo Adrian Mannarino and Lucas Pouille in the last four after they surprised top seeds Jean-Julien Rojer and Horia Tecau in three sets.