Venus is into semifinals for the second time in three majors - after a six-year absence from the last four - and for the 21st time overall. (Photo: AP)

Melbourne: Venus Williams has become the oldest woman to reach the Australian Open semifinals in the Open era, returning to the last four at Melbourne Park for the first time in 14 years.

The 36-year-old Williams beat No. 24-seeded Anastasia Pavlyuchenkova 6-4, 7-6 (3) on Tuesday, winning the last six points in the tiebreaker to seal her 50th career win at Melbourne Park.

She is into semifinals for the second time in three majors - after a six-year absence from the last four - and for the 21st time overall.

Williams hadn't reached the semifinals in Australia since 2003, the year she lost the final to her sister, Serena.

"I'm so excited," said Williams, who was playing in her ninth quarterfinal at the season-opening major since her debut at Melbourne Park in 1998. "It's wonderful to be here - but I want to go further."

She will next play either French Open champion Garbine Muguruza or CoCo Vandeweghe, who are both in the Australian Open quarterfinals for the first time.