Three years ago at the US Open, Emma Raducanu produced one of the most unlikely underdog runs in the history of sports, becoming the first player to come through qualifying and win a Grand Slam singles title.

And just when it looked like Raducanu was preparing to repeat that incredible feat at Wimbledon, another qualifier has improbably thrust herself into precisely the same position.

Lulu Sun, a 23-year-old representing New Zealand, reached the quarterfinals on Sunday with a stunning, stirring 6-2, 5-7, 6-2 win over Raducanu.

The dramatic match, including an injury timeout by Raducanu, ran 2 hours and 50 minutes.

“Oh, man,” Sun said in her on-court interview, her voice quavering with emotion, “it was a great match against her. I really had to fight tooth and nail against her.

“I’m just incredibly … I don’t even have the words right now.”

This was Raducanu’s third appearance on Centre Court this fortnight -- but the first ever for Sun. You never would have known it. Sun was relentless, never allowing Raducanu to get even a foothold in the match. In the end, the match always seemed on Sun’s attack-mode shots -- hit or miss.

"I think if you give Emma the time, she's going to take advantage of it," Sun said, "she's going to take the opportunity, which she did.

"I think staying aggressive was definitely a key point to the match. It worked well because getting her to move and getting her on the defense was what I wanted because as soon as she gets aggressive on her side, then the chance gets smaller for me."

When she’s healthy, Raducanu’s calling card is unmitigated aggression. Well, it was Sun who was the aggressor, hitting 52 winners, the highest tally of any woman at the tournament so far -- to only 19 for Raducanu.  Sun repeatedly moved forward, ultimately winning 23 of 28 points at net. Raducanu ventured to net only seven times.

Sun broke Raducanu’s serve five times.

Most casual tennis fans are familiar with the rough outline of Raducanu’s backstory, but Sun is a remarkable story in her own right.

Sun, too, has a father from Eastern Europe and a mother from China. She moved to Switzerland at the age of five and, somehow eventually wound up winning a NCAA title at the University of Texas in 2021. In her very first Wimbledon, the left-hander, ranked No.123, won three qualifying matches here and now four more in the main draw. She’s only the second woman from New Zealand to reach a major quarterfinal, following Belinda Cordwell at the 1989 Australian Open.

“That is something that definitely doesn’t come by often, and I’m super grateful to be in this situation,” Sun said after her third-round victory over Zhu Lin. “I feel definitely the support through the people and through Tennis New Zealand, and I'm super happy and grateful each round to be able to be here.”

If the seeds had held, this would have been No.8 Zheng Qinwen versus No.9 Maria Sakkari -- but Sun scuttled that scenario right out of the box, defeating Zheng in the first round. Raducanu did her part, sending Sakkari home in the third round.

As a result, the two players combined for some history when they took to Centre Court. It was only the second time in the Open Era that a qualifier and a wild card met as late as the fourth round of a Grand Slam event. This was a familiar matchup that goes back to juniors.

Sun came out flying, breaking Raducanu twice for a 3-0 lead, winning 14 of 20 points -- eight of them winners -- in a tidy 15 minutes. Raducanu broke back immediately and got it to 3-2 before Sun won the last three games to take the first set. Sun broke her serve three times.

The second set settled into a terrific battle, with both players putting all kinds of pressure on the server. Raducanu saved a break point in the third game, Sun two in the fourth and Raducanu two more in the seventh.

Serving at 5-6, Sun fought off two more break points before Raducanu scored the only break of the set. Sun’s backhand flew long and after a 73-minute second frame they were headed to a third set -- a first for Raducanu at Wimbledon.

After a lengthy bathroom break, Raducanu was serving the first game of the third set when she slipped and suffered an apparent injury to her left leg (and possibly her lower back) and was granted a medical timeout. When she returned to the court, drew herself up and fired an ace. However, Sun eventually scored a service break to jump out to a 1-0 lead, which she immediately pushed to 2-0.

Critical mass came with Raducanu serving at 4-2. On the second break point of the game, she double faulted, giving Sun an insurmountable lead.

After this matchup was set, Sun was asked if she welcomed the prospect of playing Raducanu on Centre Court.

“I would be super happy to be able to have that opportunity to play against such a great athlete,” she said. “She’s obviously been far in the Grand Slams before, and she’s, I'm pretty sure, Wimbledon's favorite since she’s from here.

“But playing on Centre and playing against her is an opportunity that I would be happy to play.”

These seven victories at the All England Club will have a pleasantly life-altering impact on Sun. Next week, she’ll vault into the Top 100 for the first time. Sun came in with a little over $300,000 in career winnings – and now she’s already banked more than that. A win in the quarterfinals over Donna Vekic would net her $750,000.

"After I passed qualies, I was super delighted because the last qualies I played at Wimbledon, I lost in the final round in three sets," Sun said. "I was super disappointed.

"When you're so close to qualifying, it kind of hurts your heart. So just getting to the main draw was a big step already."

After arriving in the fourth round, Raducanu talked about what got her there.

“I think naturally that’s always been one of my big strengths, is the big points,” she told reporters. “I step up and I thrive and I love the challenge and trying to overcome it.”

She could have been talking about Lulu Sun’s progression here this fortnight.

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