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Entering Sunday's fourth-round match on Centre Court at Wimbledon, it seemed as if the stars were aligning for another dream run for Emma Raducanu. It had already marked the best result for the British star since her breakthrough major title at the US Open in 2021, and she had recorded one of the biggest wins of her career in the round of 32 with a decisive rout against No. 9 seed Maria Sakkari.

Facing Lulu Sun, a 23-year-old qualifier playing in just her second main draw in a Grand Slam, Raducanu was the overwhelming favorite, with the crowd and in the odds, and she hadn't dropped a set during her first week at the All England Club.

But Sun was unfazed by any of it. Not the court. Nor her opponent. Nor even what was at stake.

Instead, Sun played the role of spoiler -- not dissimilar to what Raducanu had done during her star turn in New York three years ago -- and defeated Raducanu 6-2, 5-7, 6-2, to advance to the quarterfinals. Sun crouched to her knees and put her head in her hands in near disbelief when the match was over, as those seated in her player box cried in celebration.

"I was just taking it all in for the first time," Sun told the crowd during her on-court interview moments later. "I'm just super happy to play on this court in front of all of you. It was just an amazing experience."

In a sport filled with the improbable, Sun's run is still as unlikely as it gets. She is the first woman from New Zealand in the Open era to reach the Wimbledon quarterfinals -- and just the second from the country to reach the round at any major. She and Emma Navarro are the first former college players to reach this round at the All England Club since 2000, and Sun is just the seventh female qualifier to do so in the Open era.

Sun entered Wimbledon ranked No. 123 in the world -- a career high -- and with $313,832 in prize money throughout her professional career. With her win on Sunday, she is now up to No. 53 in the live rankings, and by reaching the quarterfinals has more than doubled her career earnings with a guaranteed check for at least $480,000.

Her path to the moment has been equally unconventional.

Sun was born in New Zealand in a town so small she told reporters there were "more sheep and deer than people" but raised in Switzerland. She went by her surname, Radovcic, when representing both countries during her junior career and even reached the 2018 Australian Open junior doubles final. But because of an injury that "worried" her mom, in addition to a familial emphasis on education, Sun postponed turning professional and she committed to Texas. Alongside Peyton Stearns, also a pro currently finding success on the WTA Tour, Sun helped lead the Longhorns to the national title during her freshman season in 2021.

Sun turned professional in 2022, but success at the next level was far from immediate. Spending most of her time playing in lower-tier ITF events during 2022 and 2023, Sun's ranking toiled in the 200s and 300s and she appeared in just one major qualifying draw (at Wimbledon in 2022). But Sun began to find momentum this season. She played in her first major main draw at the Australian Open in January after coming through qualifying, and in the main draws at two WTA tournaments, in addition to winning two ITF titles.

But Wimbledon has been her breakout tournament.

In her opening-round match, she fought back to stun No. 8 seed Qinwen Zheng 4-6, 6-2, 6-4, for her first victory at a major. And during Sunday's match, Sun had 52 winners -- the most by any woman all tournament -- and won 23 of 28 net points.

Raducanu, who was held to just 19 winners, credited Sun for being "very aggressive" and said she was "swinging really freely" during the match.

And now Sun has a chance to make even more history -- for herself, the tournament and her country -- as she next takes on a resurgent Donna Vekic on Tuesday with a spot in the semifinals on the line. Vekic, who defeated Paula Badosa 6-2, 1-6, 6-4 on Sunday, admitted she was largely unfamiliar with Sun's game.

"Obviously she's playing great tennis, [but] I don't know a lot about her," Vekic said. "I think the coaching team will be studying all night to try to get ready for the match on Tuesday. No one makes the quarterfinals of Wimbledon by accident. She's obviously playing great tennis. It will be a tough match."

While Sun and her team will undoubtedly be preparing equally hard for the match, Sun will likely approach it just as she's done for every clash during the fortnight -- and will try to continue to surprise herself yet again.

"I wasn't expecting to be here at this stage, but I've just been playing match by match," Sun said after her third-round victory. "Yeah, here I am."