Stan Wawrinka is through to another grand slam semi-final after surviving a tough scrap with French star Jo-Wilfried Tsonga.

After two tight sets, Wawrinka eventually broke Tsonga and ran away 7-6 (7-2) 6-4 6-3.

The 2014 Australian Open champion will now play either Roger Federer or Mischa Zverev in the final four.

Wawrinka and Tsonga were initially locked in a hostile gun fight with both players refusing to back down from the challenge.

Advertisement

The match threatened to boil over at the end of the first set when Tsonga took exception to a look he believes Wawrinka gave him as they were sitting down for the brief break at the end of the first set tiebreak.

Heated exchange at Australian Open

Stan Wawrinka and Jo-Wilfried Tsonga have exchanged heated words at the end of the first set of their quarter-final on Rod Laver Arena.

After Wawrinka hung tough to take the first set 7-2 in the first set tiebreak the pair become embroiled in a heated disagreement as they both sat at their courtside seats during the short break at the end of the set.

Speaking in French the pair reportedly clashed when Tsonga took exception to an evil look he was given by Wawrinka.

Wawrinka then responded by saying he never gave a look.

"It seemed to be a conflict about them looking at each other," Channel 7's Jim Courier said.

"Maybe Wawrinka had a stare down. This is pure speculation because it's hard to hear them talking over the music. Whatever the irritation is it was coming from Jo. Jo was the one who was aggravated and expressed displeasure. Stan was trying to figure out when he did it.

"Whatever it is, Stan didn't think he did anything. There is a little tension in this match."

Vandeweghe beats Muguruza

Coco Vandeweghe is through to the semi-finals at Melbourne Park.

She won the first set of her match against Garbine Muguruza 6-4 in 55 minutes as neither player really managed to take the contest by the scruff of the neck.

Early in the second set, commentator Sam Smith was bewildered by Muguruza's unwillingness to attack Vandeweghe's backhand - clearly her weaker wing - hitting to it just 44 per cent of the time. Smith said male players would be far more willing to take advantage of an opponent's vulnerability in such a situation.

"If this was a men's match in the same situation, the men would be going to the weakness 80 to 90 per cent of the time," she said. "They're so much more ruthless. I don't see where Muguruza is going with this game plan."

But it looked like nothing could stop Vandeweghe as she fed the Spaniard a bagel in just 28 minutes in the second set to secure the 6-4 6-0 victory.

From the outside it seemed the American was in complete control of her game, but as she revealed in her on-court interview, looks can be deceiving.

"I really wasn't feeling all that great out there, I was feeling kind of nervous," Vandeweghe said. "I even told my coach, 'Better get some toilet paper out there because, you know ...'

"It was really quite frustrating for me to have so many break point opportunities ... I was second guessing myself on what to do with the returns.

"I fought through a few break points on her serve and kept the pressure on in the first set and then she finally cracked and once I got rolling in the second it was like a freight train, you couldn't stop it."

The 25-year-old takes on Venus Williams - a player Vandeweghe has grown up admiring - in the semis.

"It's an honour to play a great champion like Venus - someone I grew up watching play tennis and who I used to chase for an autograph," Vandeweghe said. "It took two of her matches to push through the crowd to get the autograph.

"I told her about it one time in the Fed Cup when we were on the same team. I said, 'Venus, the first time I asked for an autograph, I couldn't get one'. And she said, 'Do you want one now?' I said, 'No thanks because I don't have a pen or a tennis ball'."

Vandeweghe goes one set up

Coco Vandeweghe won the first set of her match against Garbine Muguruza 6-4.

No player managed to take the match by the scruff of the neck and the American needed 56 minutes to grab her early lead.

Early in the second set, commentator Sam Smith was bewildered by Muguruza's unwillingness to attack Vandeweghe's backhand - clearly her weaker wing - hitting to it just 44 per cent of the time. Smith said male players would be far more willing to take advantage of an opponent's vulnerability in such a situation.

"If this was a men's match in the same situation, the men would be going to the weakness 80 to 90 per cent of the time," she said. "They're so much more ruthless. I don't see where Muguruza is going with this game plan."

Roddick's emotional message

Andy Roddick has sent an emotional message to his former agent after being announced as one of the latest International Tennis Hall of Fame inductees.

Ken Meyerson represented Roddick during his career, but passed away in 2011 after suffering a heart attack. Clearly, he's still in the tennis star's thoughts.

Williams advances into semi-finals

Venus Williams is the first woman to advance to the Australian Open quarter-finals after overcoming Anastasia Pavlyuchenkova in straight sets 6-4 7-6.

It's the first time the American has made it to the final four at Melbourne Park in 14 years.
In a match with plenty of breaks of serve, it was the 36-year-old's power and mobility that gave her the edge over her Russian opponent. Pavlyuchenkova hit hard from the baseline as well, but rarely capitalised after breaking Williams' serve.

"I want to go further, I'm not happy just with this, but I'm happy I have the chance to go further," Williams said.

Playing under the Melbourne sun offered more challenges than just dealing with the heat, Williams revealed.

"It's not easy playing at this time of day," she said. "The sun is explosive. Looking up into the solar flare, and you're like, 'Oh my God - I can't see the ball'.

"It's challenging. We both dealt with it. It wasn't easy, but that's what tennis is."

Ballkid's gaffe causes point to be replayed in 'big babe tennis' match

This is what "big babe" tennis looks like.

That was the term Channel Seven's Rennae Stubbs used to describe what the crowd at Rod Laver Arena and those watching on TV at home were witnessing between Venus Williams and Anastasia Pavlyuchenkova.

Both players' serving was poor, but their hitting was huge. Williams and Pavlyuchenkova pounded their ground strokes, making it increasingly difficult for either of them to stay in a rally for very long when one got the upper hand.

Midway through the second set when Pavlyuchenkova was serving at 1-2 down, the pair had only engaged in a rally longer than nine shots three times. Additionally, just under 40 per cent of the total points played had lasted for four shots or fewer.

"That's why we are calling it big babe tennis," Stubbs said. "These two aren't mucking about. See ball, hit ball."

Generally with baseline warriors you expect long rallies as the players try and wear each other down, but Williams and Pavlyuchenkova were just hitting so hard that neither could get into the grind.

That alone is strange, and so too is the fact that at one stage during the match, a point had to be replayed for a very rare reason - one of the ballkids dropped a ball.

Venus takes first set of 'big babe tennis'

Venus Williams' big hitting helped her take the first set 6-4 in her quarter-final clash against Anastasia Pavlyuchenkova.

Both women struggled to hold serve in the opener, but Williams improved most as the set wore on to gain the early advantage.

Pavlyuchenkova's power game was on song too in an intriguing baseline battle, but the American's mobility around the court gave her the edge. The intensity of the match led Channel Seven's Rennae Stubbs to label the contest "big babe tennis".

"You called it big babe tennis and that's exactly what it is," co-commentator Sam Smith added.