Vasek Pospisil and Jack Sock defeated Sam Groth and Lleyton Hewitt 6-4, 6-2 in their-third round doubles match at the Australian Open on Sunday. 

Pospisil, from Vernon B.C., and his American partner received a walkover to the third round after the opposing side of Robin Haase and Fernando Verdasco withdrew prior to the start of the second round two days earlier.

Fellow Canadian Daniel Nestor is also headed to the fourth round as he and teammate Radek Stepanek downed Pablo Andujar and Pablo Carreno Busta 5-7, 6-4, 6-4.

Australia's Hewitt, who announced that he would end his career after this year's tournament, walked off the court and into retirement to a standing ovation in the 7,500-seat Margaret Court Arena. 

A centre-court ceremony was held for the 34-year-old on Thursday following his second-round singles loss to David Ferrer. 

Serena Williams through to quarter-finals

Six-time and defending champion Serena Williams is through to the quarter-finals at Melbourne Park after a 6-2, 6-1 win over Russian Margarita Gasparyan on Rod Laver Arena in 55 minutes.

Under bright sunshine after the roof was opened following morning rain, Williams lost her service in the opening game but quickly found her groove to set up a rematch of last year's final with Maria Sharapova, who defeated Belinda Bencic in the preceding match.

Williams has beaten Sharapova in 18 of 20 matches and hasn't lost to Sharapova since 2004.

​Sharapova advances to face Williams

Maria Sharapova is through to the quarter-finals after a 7-5, 7-5 win over Belinda Bencic of Switzerland.

The fifth-seeded Sharapova needed 2 hours, 5 minutes to beat Bencic, breaking the Swiss players serve for the fourth time in the last game — sealing it when she successfully challenged a call on the baseline on the opposite end of the court.

Sharapova, the 2008 champion and a three-time runner-up, needed four set points to clinch the opening set, including two in the 10th game.

Bencic again found herself on the wrong end of an opponent's aces count. Sharapova had 21, including four on her second serve. Last year, Bencic was on the receiving end of a WTA-record 27 aces from Sabine Lisicki.​

Nishikori defeats Tsonga

Kei Nishikori was the first male player through to the quarter-finals, defeating Jo-Wilfried Tsonga 6-4, 6-2, 6-4 in front of a hugely partisan crowd filled with flag-waving Japanese fans.

The seventh-seeded Nishikori also reached the quarterfinals at the Australian Open last year and in 2012.

Nishikori has had trouble with Tsonga's power game in the past, losing most recently to the Frenchman in the quarterfinals of the French Open last year.

But Tsonga lost his serve five times in the match and only managed to break Nishikori once.

Djokovic perseveres

Djokovic survives scare at Aussie Open0:42

An error-riddled Novak Djokovic has advanced to the quarterfinals of a Grand Slam tournament for the 27th consecutive time, persevering over a dogged and determined Gilles Simon 6-3, 6-7 (1), 6-4, 4-6, 6-3 in a 4-hour, 32-minute match at Melbourne Park.

Djokovic advanced to the final eight and a match Tuesday against Kei Nishikori despite making a whopping 100 unforced errors, including four backhand drop shots into the net as he attempted, unsuccessfully, to get Simon to move up from his anchored position on the baseline.

The five-time champion Djokovic and the pesky Simon played plenty of long rallies — the longest of which was 37 strokes. Simon frustrated Djokovic with his defensive play, saving all 11 break-point opportunities in the second set before dominating the tiebreaker.

Overall, Simon saved 19 of 25 break points.

Federer unfazed by late start

Federer advances at Aussie Open with straight sets win0:34

Roger Federer ensured he didn't have too late a night on Rod Laver Arena, beating David Goffin 6-2, 6-1, 6-4 to advance to the quarterfinals at Melbourne Park.The four-time Australian Open champion didn't get on court until 10:45 p.m. because of to late-finishing matches in the afternoon and a subsequent delayed start to the night program.

But the third-seeded Federer raced through the match in 1 hour, 28 minutes, finishing up shortly after midnight.

Federer plays No. 6-seeded Tomas Berdych in the quarterfinals.

With files from CBC Sports