Leylah Fernandez was a single game away from defeat in Saturday's Mubadala Citi DC Open semifinals, but she battled all the way back to pull off a grueling, three-tiebreak victory and reach her first final in over a year.

On another toasty day in the American capital city of Washington, D.C., Canada's Fernandez overcame No. 3 seed Elena Rybakina of Kazakhstan 6-7(2), 7-6(3), 7-6(3) in a 3-hour and 12-minute marathon.

Washington, D.C.: Draws | Scores | Order of play

There was nearly a rematch of the memorable 2021 US Open final on Sunday, but it was not to be. Instead, Fernandez will face Anna Kalinskaya, who eased past 2021 US Open champion Emma Raducanu 6-4, 6-3 in the day's second semifinal.

Sunday is a huge chance for World No. 36 Fernandez and World No. 48 Kalinskaya, both of whom have previously been ranked inside the Top 20. This WTA 500 trophy would be the biggest career title for either of them -- in fact, Kalinskaya has yet to win a WTA singles title at all.

Fernandez narrowly defeated Kalinskaya in their only previous meeting, which was over four years ago. On the hard courts of Guadalajara in 2021, Fernandez squeaked past Kalinskaya 7-5, 4-6, 6-4.

The final is at 2:30 p.m. Sunday afternoon local time (7:30 p.m. BST). Let's break down the cases for the two unseeded finalists:

Advantage, Fernandez

In Saturday's first semifinal, Elena Rybakina had not lost serve through 7-6(2), 5-4, where she served for the match. Naturally, Leylah Fernandez had her exactly where she wanted her.

'When I first started playing tennis, there was like a mini camp and they were doing a physical test, kind of a straight-line sprint,' Fernandez said after her quarterfinal win on Friday. 'I was probably the slowest out of all of the girls there.

'The coaches were concerned, like 'She's not very good physically.' They talked to my parents, and my parents said, 'Yeah, but if you put a tennis ball in front of her and you ask her to run for every ball, she's gonna do it. Her heart and her belief in herself is much bigger than most of the girls in that camp.''

Heart and belief continue to pull Fernandez into and through bigtime matches. Toting a water bottle emblazoned with the words 'hard work' and 'fight,' Fernandez never lets a match go.

That came to pass in her epic win over Rybakina. Staring down match game at 5-4 in the second set, Fernandez's cracking returns helped the Canadian earn her first service break of the day when she needed it most. 

Once the third set hit, Fernandez was the sturdier player in rallies down the stretch. Bolstered by her never-say-die attitude, these returns and rally groundstrokes could lead Fernandez to her fourth career title, and her first since 2023 Hong Kong. All of her three career WTA singles titles have come on hard court.

'We're doing things right,' Fernandez said on Saturday. 'The results are going to come. [I'll] keep enjoying it, and to not focus too much on results but focus on how my game is improving.'

Advantage, Kalinskaya

On paper, Anna Kalinskaya has 'upset' three players ranked ahead of her in her last three rounds. However, Washington is starting to feel like a home-field event for the former World No. 11.

The Mubadala Citi DC Open is arguably Anna Kalinskaya's best stop on tour. She holds a 9-2 main-draw win-loss record at the event and has never lost before the quarterfinals here, including a semifinal showing in 2019 as a qualifier ranked No. 160.

Kalinskaya went one further this year and is into her second career WTA singles final, following WTA 1000 Dubai and WTA 500 Berlin, both last year. After narrow losses in both of those finals, she has another opportunity to join the club of WTA singles titlists.

These hard courts suit Kalinskaya's unfussy groundstrokes and placid demeanor. Dominating with her forehand, Kalinskaya had 19 winners to Raducanu's 13 in their opening set.

Proving she is lethal from both wings, Kalinskaya fired consecutive backhand winners to break Raducanu in the opening game of the second set, and she was off to the races from there.

'I always like to be aggressive,' Kalinskaya said on Saturday night. 'I like that style of the game. Yeah, I guess the fast court fits me very well, but you need to be fast at making decisions. It's also very challenging.

'But I guess when I serve good, return fast, that's what I like the most, and to try to be aggressive as much as I can, and the fast court helps.'

If she can find the holes to power past speedy Fernandez on Sunday, Kalinskaya could be hoisting the champion's trophy for the very first time at tour level.