Serena Williams lauded her own fighting qualities after beating top seed Simona Halep 6-1, 4-6, 6-4 in a thrilling contest to reach the Australian Open quarter-finals on Monday.
Williams, a seven-time champion at Melbourne Park, looked to be cruising to victory when she bulldozed through the first set in just 21 minutes, reeling off six straight games having lost her opening service game to love.
However, Halep displayed all the powers of reserve that led her to the French Open title last year by battling back from an early break in the second set to level the match.
After holding off a break point in the first game of the deciding set, the world No 1 from Romania looked to have seized control, but her failure to clinch any of three break points at 3-3 proved costly, with Williams earning the all-important break in the next game.
The American 16th seed then closed out the match with a comfortable service hold to maintain her hopes of winning a record-equalling 24th grand slam title.
"I'm such a fighter, I never give up," said 37-year-old Williams, who takes on Czech seventh seed Karolina Pliskova for a place in the semi-finals.
"It was an intense match and there were some incredible points but I love playing tennis and being out here and I love this court; it's really cool to be back."
Williams has been in ominous form at Melbourne Park but faced a major step up in class against last year's beaten finalist.
"I really needed to elevate my game. She's a great player," Williams said. "I can definitely go to a new level. I have to if I want to stay in the tournament."
With the victory secured and just seven other women remaining in the tournament, Williams is the overwhelming favourite to win her first tournament since the last time she was at the Australian Open in 2017.
On that occasion, Williams won the title while eight weeks pregnant and subsequently sat out the remainder of the season. Upon her return in 2018 - a season that was severely limited - she managed to reach the Wimbledon and US Open finals.
Williams denied her win over the world No 1 after not playing since September was a poor reflection on the state of women's tennis.
"I think it says more about me than women's tennis ... women's tennis is amazing," she said. "It's at the highest level it's ever been ... it's tough out here."
Halep now risks losing her status as the world's top-ranked player, with world No 4 Naomi Osaka, No 6 Petra Kvitova, No 7 Elina Svitolina, and world No 8 Pliskova all with potential routes to top spot.
However, the Romanian said she is not concerning herself over the rankings.
"I will not stress myself about this," she said. "I just go home, I will rest, and I will watch tennis. I am also curious who is going to win."