Serena Williams set up a blockbuster Australian Open semi-final with Naomi Osaka after producing her best performance of the tournament to defeat Simona Halep 6-3, 6-3 on Tuesday.
The 39-year-old American went toe-to-toe with the Romanian second seed over 80 engrossing minutes on Rod Laver Arena before she was finally able to move to within two victories of a record-equalling 24th Grand Slam title.
The victory serves as a measure of revenge for the last time the pair played when Halep defeated Williams in the 2019 Wimbledon final.
Williams, who mixed 24 winners with 33 unforced errors over the contest, has not won a major since her seventh Australian Open triumph in 2017, losing four successive major finals since then.
The third of those four defeats came against Osaka in the 2018 US Open final, so Williams will have another shot at revenge.
"Definitely think this is the best match I have played this tournament, for sure," said Williams after reaching her 40th Grand Slam semi-final.
"Obviously I had to be going up against the number two in the world, so I knew I had to do better, and that's what I did and I'm excited."
For Halep, who reached the semi-finals last year and was losing finalist in 2018, it was back to the drawing board as she looks to add to her two Grand Slam titles at the French Open and Wimbledon.
Williams will need to deliver a similarly impressive display when she faces Osaka, who maintained her bid for fourth major title after crushing Hsieh Su-wei 6-2, 6-2 earlier in the day.
Osaka is aiming to win the Australian Open immediately after claiming the US Open for a second time – she previously achieved the feat in 2018 and 2019 – and her win over Hsieh was markedly easier than their last meeting at Melbourne Park.
Osaka had a torrid time against Hsieh in 2019, having to come back from a set and a break down on the way to claiming the championship.
But the 23-year-old Japanese star had no such problems in Tuesday's match inside Rod Laver Arena as she dominated from start to finish to wrap up victory in 66 minutes.
"Yeah, definitely really happy," Osaka said on-court. "Really happy with how I played today. Every time I play her it's a real battle and, despite the score, this was again a real battle today."
Hsieh, 35, bowed out after a stellar tournament, having become the oldest women's player to debut in a Grand Slam quarter-final in the professional era.
The improbable angles conjured by her double-handed, double-sided game had Osaka in some trouble early, but Hsieh was unable to convert any of the three break points she raised in the opening games of the first set.
Osaka quashed the first of them in the opening game with an ace down the 'T' before smashing Hsieh's defences with a blazing backhand down the line to break to 3-1.
After holding on grimly through a 14-point game to hold serve, Osaka raised the pressure when Hsieh served to stay in the set at 5-2 and sealed it when the Taiwanese slapped a limp backhand wide.
Hsieh was soon in a tailspin, pounding a backhand well over the line to be broken to 2-0 as an emboldened Osaka raced to the finish.
While Osaka has suffered some major wobbles in the past, there was no hint of frustration despite Hsieh saving two match points. She bided her time to claim the win on the third when an overwhelmed Hsieh floated a sliced backhand long.
"I would say it makes me a bit more calm, realising that even when my back was against the wall, I still had chances," said Osaka, who saved two match points in a cliffhanger against Garbine Muguruza in her previous match.
"Even today when I had two match points and she saved them ... I was a bit more calm."