American Amanda Anisimova called Saturday at Wimbledon "the most special day of my career." A win was just icing on the cake.

The 20-year-old No.20 seed rallied from a set down to defeat compatriot Coco Gauff, seeded No.11, in her Centre Court debut to reach the fourth round at the Championships for the first time. After dropping the first set from a winning position, Anisimova bounced back in 2 hours, 7 minutes for a 6-7(4), 6-2, 6-1 win. The two young compatriots have now split their two career meetings on the pro tour.

"It's my first time playing on Centre Court. It's the most special day, I think, of my career," Anisimova said in her on-court interview. "It's just a huge privilege to play on this court ... playing Coco. She's an amazing player and just got to the finals of a Grand Slam. Before the match, I was just trying to prepare myself to soak in this moment whether I win or lose. Winning today is just so special.

"I think the worst thing for a tennis player is to lose 7-6 in the first set. ... It's really important to just bounce back and give everything I have. It was very easy to do, especially on this court, even though it was extremely exhausting."

Tale of the tape: Both players led by a break in the first set. Gauff started the stronger of the two and led 3-0 before Anisimova won four games in a row. After more than an hour of play, the set went Gauff's way in a tiebreak. From 4-1 down, Gauff won the last six points. 

Anisimova rebounded emphatically; she broke Gauff's serve three times in the second set and twice in the third to complete the comeback. Though the nerves were apparent in the biggest match between the peers so far, Anisimova found a winning strategy and stuck to it. She broke down Gauff's forehand, and finished when the opportunity arose. Though she hit twice as many unforced errors as Gauff did, she also hit 10 more winners. 

Up next: Anisimova will next face France's Harmony Tan, whose career-defining tournament continued with a 6-1, 6-1 rout of Great Britain's Katie Boulter in Round 3. The pair have, in fact, played at a Grand Slam before; in her semifinal run at Roland Garros three years ago, Anisimova was a 6-3, 6-1 victor over Tan in the first round. 

Harmony Tan stays cool to reach Wimbledon second week

Tomljanovic rallies to return to second week

Last summer, Ajla Tomljanovic reached the quarterfinals of a Grand Slam for the first time at Wimbledon, where she was beaten by eventual champion and fellow Aussie Ashleigh Barty. A year later, she's back in Week 2 thanks to a 2-6, 6-4, 6-3 victory against No.13 seed Barbora Krejcikova.

Nearly repeating the result, Tomljanovic says, has given her confidence. 

"Coming in, you're not seeded so you don't know what can happen. Even if you are, it's a Slam. There is always upsets," she said. "I don't know what really my form was coming in, but I just knew that I could produce good tennis, but actually doing it, it feels really nice. Just kind of confirms that I maybe do belong here."

Jimmie48/WTA

After dropping serve three times in the first set, Tomljanovic rounded into form as she grew more accustomed to the Czech's style of play. She forced a decider by breaking serve in the 10th game of the second set, and got the decisive service break in the sixth game of the third. She never faced break point in the final set until the last game, where she saved two before winning the match.

"It was a tough start," Tomljanovic said. "I have never faced her, and it really caught me off guard how she mixes up the pace and completely lost my intensity. You know: what I came with, the idea of what I wanted to do on the court.

"Luckily I didn't let it keep going for longer than that first set. I managed to play a little bit more on my terms. I just fought through that second set. Then I feel like that third was just playing good tennis. I think like the few clutch moments that I played well, where I was down Love-30, and just really pleased to close it out."