Johanna Konta outclassed eighth seed Venus Williams 6-4 6-2 to reach the second round of the Australian Open.
Britain’s number one, 24, raced to victory in 79 minutes as seven-time Grand Slam champion Williams, her left thigh heavily strapped, struggled.
Konta denied that 35-year-old Williams’ age had anything to do with the American’s laboured display.
“It’s irrelevant how old she is because she’s such a champion with so much experience and knowledge,” said Konta.
“Even if she’s playing with one leg out there, you’ve got to really take care of things on your own because she’s an incredible player. I have all the respect for her in the world.”
Where the match was won
Konta hit five aces to Williams’ one and won 71% of her points on first serve compared to just 52 from Williams.
Konta leads British women’s challenge
Konta, who reached the last 16 at the 2015 US Open, is the only British woman left in the singles draw following Heather Watson’s defeat on Monday.
The world number 47, making her Australian Open debut, will now face either Carina Witthoeft or Saisai Zheng.
Andy Murray also won to join Konta in the second round but Dan Evans and Aljaz Bedene both went out.
Relive the action as Konta and Murray progress
Beating a legend ‘still very much a blur’
Venus first played at the Australian Open in 1998 and reached the final in 2003
The Briton, who has described Williams as her idol, moved her opponent around the court and hit deep into the corners to take control of the match.
Konta broke serve twice in the first set and then eased to a 5-0 lead in the second before the American rallied briefly.
But Konta held her nerve to secure a famous victory over the former world number one.
“Right now it is still very much a blur,” added Konta, who lost in the first round at her two warm-up tournaments.
“When the draw came out and I saw who I was playing, I was just hoping to stay out there more than an hour.
“I played two previous tournaments and didn’t quite get the results I wanted but I have a very strong belief in the way I want to play and the way I want to be thinking.”