The ASB Classic women's final today will be an endurance test for 18-year-old Canadian sensation Bianca Andreescu.
She has already played seven matches at Stanley Street, and spent more time on court that any other player in the tournament.
After coming into the tournament with a back strain, which she has managed over the event, Andreescu has been an iron woman.
Three of her matches had gone for more than two hours, including the late night epic against Williams which stretched on for 144 minutes.
She has spent more than 12 hours on court, and has been battling a cold since Thursday. In contrast, her 30-year-old German opponent Julia Goerges has been on court for slightly more than six hours.
Andreescu will be the underdog tomorrow against the experienced Goerges. She is in her 14th WTA final and has a remarkable record at the ASB Classic, winning more matches than any other female in history.
But the Canadian, who was playing second and third-tier events on the tour last year, can't be counted out. Surely.
Andreescu has faced every challenge this week head-on and mastered it. She might be running on adrenalin and nerves, but that's been enough so far.
Compared to the pyrotechnics she produced against both Williams and Caroline Wozniacki, today's 6-3, 6-3 win over Su-Wei Hsieh was a less spectacular affair, but no less impressive.
Before this week, Andreescu had beaten only one top-50 player in three years on tour. Now she has toppled three of them, including two former world No1s, across three remarkable nights.
Hsieh is a tricky opponent. She has plenty of experience, with three WTA titles over nearly two decades on tour. Hsieh reached the fourth round at two Grand Slams last year, beating world No1 Simona Halep at Wimbledon on the way.
Her unorthodox game, with plenty of slice, no pace on the ball and great angles and placement can be tough to counter.
But Andreescu rose to the occasion again.
She spent most of the match camped inside the baseline, dictating the points with a calm authority.
The Canadian has the perfect blend, able to generate incredible power off both wings, but also capable of delicate, disguised drop shots.
And most of all, she's living this incredible dream, which just goes on and on.
"A lot has happened," said Andreescu. "I've worked really hard for this moment. There have been a lot of tough times. Seeing a lot of the younger players doing well gives me inspiration."