There's no crowd at the US Open this year to pull for Serena Williams and will her to victory so she provided her own encouragement in a tough fourth-round win on Monday.
"Keep fighting!" Williams exhorted herself.
Williams came back from a third-set deficit against Maria Sakkari, who she lost to less than two weeks ago, to prevail 6-3 6-7 (6-8) 6-3 and take another step closer to a record-equalling 24th grand slam title.
"I feel like I'm pretty vocal with or without a crowd. ... I'm super passionate," Williams said after she advanced to the quarter-finals at Flushing Meadows for the 16th time.
"This is my job. This is what I wake up to do. This is what I train to do, 365 days of the year.
"Yeah, I'm always going to bring that fire and that passion and that 'Serena' to the court."
When the match ended, after Williams collected six of the last seven games, she turned and yelled toward her husband, who stood at his front-row seat and yelled right back.
Williams was two points from victory at 6-all in the second-set tiebreaker, but faltered to let Sakkari back into the match.
But as is so often the case, when the outcome was hanging in the balance in the third set, which Sakkari led 2-0 but couldn't quite get to 3-1, Williams was better when it mattered the most.
"I have to be deadly honest, I wasn't brave enough in the third set," Greek 15th seed Sakkari said.
"I kind of like, not choked, but didn't (convert) my chances.
"And if you don't get your chances with a good Serena against you, it's done."
Six-times US Open winner Williams, who turns 39 in less than three weeks, will face unseeded Tsvetana Pironkova for a semi-final berth.
Playing in her first tournament in more than three years after taking time off to have a child, the 32-year-old Pironkova advanced with a 6-4 7-6 (7-5) 6-3 victory over Frenchwoman Alize Cornet.
The Bulgarian then choked back tears while talking about her son Alexander.
"I haven't seen him in two weeks," she said.
"It's very tough, it gets tougher every day.
"I know he's watching me and I know he's proud of me - and it's worth it."
Former world No.1 Victoria Azarenka became the third mum to advance to the last eight on Monday when she fought back from a set down to beat Karolina Muchova 5-7 6-1 6-4.
Unseeded Azarenka, who is a two-time Australian Open champion, is through to her first grand slam quarter-final in more than four years.
The 31-year-old Belarusian marched on to a last-eight date with 16th-seeded Elise Mertens.
Belgian Mertens ended the tournament of Australian Open champion and tournament second seed Sofia Kenin 6-3 6-3.