Serena Williams has vowed to keep going in her bid to win a record-equalling 24th grand slam title.
The 37-year-old American lost her fourth final since she became a mother when Canadian teenager Bianca Andreescu beat her 6-3 7-5 at the US Open.
Since she returned after giving birth, Williams has reached two finals at Flushing Meadows and two at Wimbledon, only to come up short each time.
She lost in acrimonious circumstances to Naomi Osaka here last year, while Angelique Kerber and Simona Halep denied her in SW19.
Undoubtedly just reaching those finals is an incredible achievement, but Williams was struggling to take too many positives in the aftermath of her latest defeat.
"I feel like in 20 years, I definitely will be like, 'Wow, that wasn't so bad'. It's very hard to take this and say you did OK, because I don't believe I did.
"I definitely fought. I mean, Kerber doesn't count because, like, I was exhausted. My baby was eight months old, and that's tough.
"But all of it, honestly, truly, is super frustrating. I'm like, so close, so close, so close, yet so far away.
"I don't know what to say. I guess I got to keep going if I want to be a professional tennis player. And I just got to just keep fighting through it."
Andreescu received congratulations from the Canadian prime minister Justin Trudeau after becoming the first player from the country to win a grand slam title.
The 19-year-old will be the world number five when the latest rankings come out, but she has her sights set even higher.
"My goals have been to just win as many grand slams as possible, to become number one in the world," she said.
"It's been a goal of mine to inspire many people, especially Canadian athletes.
"I think that this win will hopefully do that, not only this win but just what I've accomplished this past year because so many Canadian athletes have paved the way for me when I was young.
"Hopefully I can be that person to them."