The Insider Wrap is a recap of everything you need to know from the week that was. This week, WTA Insider looks back at the 2021 US Open, which will go down as one of the most thrilling two weeks of tennis the sport has seen in recent years. From remarkable underdog comebacks to an all-teenage final that produced a history-making champion, the 2021 US Open is a tournament we won't soon forget.

Performance of the Tournament: Emma Raducanu

It's been 48 hours since 18-year-old Emma Raducanu fell to the court in disbelief on Arthur Ashe Stadium after completing an undeniably stunning and historic run to the US Open title. After just finishing school earlier this year, she played her first WTA event three months ago and came into the US Open qualifying without a main-draw match on the WTA Tour. (Her professional wins either came at Wimbledon or at the lower levels.) Raducanu yet to face a Top 40 opponent.

Maybe experience is overrated. 

READ: The improbable run of Emma Raducanu

Ranked No.150, Raducanu blitzed through 10 consecutive matches - three in qualifying and seven in the main draw - to become the first qualifier in the Open Era to win the US Open title. She ended Britain's decades-long drought of a women's singles major champion and the youngest woman to win a major since 17-year-old Maria Sharapova won Wimbledon in 2004. 

Raducanu's triple-digit surge up the rankings puts her at No.23 and No.14 on the Porsche Race to the WTA Finals. With a bevy of points still available during the fall season - Indian Wells will play a big role in WTA Finals qualifying - could Raducanu seal a stunning Top 10 debut? A month ago, she thought acing her math A levels was going to be the highlight of her 2021. Now? The sky's the limit.

Social Buzz: Halep, Roddick, Royals lead cheers for Raducanu after US Open win

Surprise of the Tournament: Leylah Fernandez

On paper and match after match on the showcase stage that is Ashe Stadium, no one performed better in the face of adversity and competition as Canada's Leylah Fernandez. The 19-year-old had not won back-to-back main-draw matches since winning her maiden title in Monterrey in March. She was sitting at No.73 at the start of the US Open.

Then Fernandez started slaying seeds. To the naked eye, Fernandez looked to be overpowered and out-experienced in every match she played in New York. But she stood toe-to-toe with the tour's biggest hitters. She tallied wins against Ana Konjuh, Kaia Kanepi, last year's champion Naomi Osaka and Aryna Sabalenka, as well as the game's premier grinders, Angelique Kerber and Elina Svitolina. 

Read: Why Fernandez's father doesn't have a ticket to the US Open final

In total, Fernandez defeated three of the Top 5 players. You would be hard-pressed to find a more difficult path to a major final in recent years. 

Read: How Fernandez won New York hearts at the US Open

Fernandez's output finally caught up to her in the final against Raducanu, and while Fernandez fought and scrapped to knock Raducanu off her rhythm, the Brit never doubted and never blinked. Raducanu was the better player on that day without question, but there's an argument to be made that Fernandez had the better tournament.

Honor Roll

Samantha Stosur and Zhang Shuai: The US Open doubles champions reunited after a long break due to Covid and the Olympics, and the duo can't stop winning. Stosur and Zhang won the Western & Southern title, their third career championship, with a match-point-saving effort, then cruised to their second major title, defeating Coco Gauff and Caty McNally in the US Open final

Champions Corner: How the US Open title will quiet the retirement talk surrounding Stosur and Zhang

Maria Sakkari: The Greek star should focus on how her New York fortnight went as opposed to how it finished. She knocked off three Top 10 seeds in Petra Kvitova, Bianca Andreescu and Karolina Pliskova to make her second Slam semifinal of the season. Her win over Andreescu was a memorable, physical display. Sakkari's win over Pliskova was a serving masterclass. She'll be disappointed at her inability to set aside the nerves and play at her best against Raducanu, where she lost 6-1, 6-4, but she leaves New York at No.6 on the Porsche Race Leaderboard.

Rankings Watch: Raducanu and Fernandez surge as Hsieh retakes Doubles No.1

Shelby Rogers and Ashleigh Barty: Arthur Ashe Stadium was home to a raucous crowd nearly every night, and Rogers and Barty played their part in the third round. The World No.1 had appeared to turn things around and served for the match at 5-2, double-break, in the third before faltering. Rogers rode the wave and mounted the unlikely comeback, playing a tactically perfect deciding tiebreak to win 8-6 in the third. 

But what puts the duo on the list is what happened after the match. The mutual admiration the women expressed in the press room was a credit to their sportsmanship, friendship and thoughtfulness. After the tournament, the USTA awarded Barty with the 2021 US Open Sportsperson Award.

Karolina Pliskova: The Czech will be left scratching her head as to what happened against Sakkari in the quarterfinals, where she played a flat-footed match to lose 6-4, 6-4. Then again, Pliskova had no business being there in the first place. The No.4 seed was down match point to Amanda Anisimova in the second round before engineering an escape to win 7-5, 6-7(5), 7-6(7). Pliskova had title ambitions in New York, but her runs through her past four tournaments are as good as anyone: Wimbledon finalist, Montreal finalist, Cincinnati semifinalist, US Open quarterfinalist.

News: WTA Finals to be held in Guadalajara, Mexico

Iga Swiatek: The 20-year-old made her first US Open Round of 16 and accomplished something no one on tour has done this season by making the fourth round or better at all four majors. Swiatek's No.8 ranking may be bolstered by her 2020 Roland Garros points, but it's worth noting that she sits at No.5 on the Porsche Race Leaderboard, which counts only the points earned in 2021. The high-achieving Swiatek may get down on herself sometimes, but she is having a remarkable sophomore season. No slump here.

Belinda Bencic: The Olympic gold medalist has showed no signs of stopping since Tokyo, booking a spot in the US Open quarterfinals with impressive wins over Jessica Pegula and Iga Swiatek. The quiet shake of the head as she walked off court after losing 6-3, 6-4 to Raducanu summed up her missed opportunity to seal her summer with a first major title. 

Simona Halep: If you were to tell the former No.1 at the start of the summer hardcourt season that she would be in the second week of the US Open after all her injury woes and rust concerns, she would have thought you were joking. Halep has been snake-bitten time and time again in New York, but this year she scored great wins over Montreal champion Camila Giorgi and Elena Rybakina before bowing out to Elina Svitolina in the Round of 16.

Sloane Stephens: Results are meaningful, but don't let them obscure a player's level. Stephens continues to trend up and given how the tournament played out, it's hard not to wonder what would have happened if the 2018 champion didn't have the toughest first three rounds of the tournament. Stephens' 6-3, 1-6, 7-6(7) win against Madison Keys in the first match of the tournament on Ashe set the tone for the event. She followed it with a straight-sets win over Coco Gauff and a tough three-set loss to Kerber. 

Aryna Sabalenka: The World No.2 made her second straight Slam semifinal with such ease that it's easy to forget that just three months ago she had yet to make a quarterfinal. The final game to get broken against Fernandez in the semifinals will cause some sleepless nights, but the 23-year-old should feel assured that making it deep at a Slam is no longer the fraught endeavor it once ones. 

Desirae Krawczyk: The American teamed up with Britain's Joe Salisbury to capture win her third mixed doubles title of the season, putting her alongside a list of big names: 

Notable Numbers

0: Number of three-set matches Emma Raducanu has played on either the WTA Tour or at the Slams.

2014: Before Raducanu, the last time a woman won the US Open singles title without losing a set (Serena Williams).

2: Matches played at the 2021 US Open that set the tournament record for longest match. Both matches lasted for 3 hours and 40 minutes and were played the same night: Elise Mertens d. Rebecca Peterson 3-6, 7-6(5), 7-6(5), and Rebeka Masarova d. Ana Bogdan 6-7(9), 7-6(2), 7-6(9).

6: Match points saved by Mertens against Peterson. The Belgian went on to make her fourth consecutive Round of 16 in New York.

4: Consecutive three-set matches won by Leylah Fernandez to make the US Open final. She defeated No.3 Osaka, 5-7, 7-6(2), 6-4, No.16 seed Kerber, 4-6, 7-6(5), 6-2, No.5 Svitolina 6-3, 3-6, 7-6(5) and No.2 Sabalenka 7-6(3), 4-6, 6-4.

24: Aces struck by Karolina Pliskova in her match-point saving win over Amanda Anisimova in the second round, setting a new tournament record for most aces in a women's singles match at the US Open, a new personal best and the most on tour in 2021. 

22: String of consecutive service points won by Maria Sakkari in her 6-4, 6-4 quarterfinal win against Pliskova. 

84: Minutes it took for Belinda Bencic to win the first set against Iga Swiatek, 7-6(12) in their tense Round of 16 clash. 

1: Number of players who won five games in a set off Emma Raducanu in New York. No.190 Mariam Bolkvadze of Georgia came closest to taking a set off Raducanu, losing 6-3, 7-5 in the second round of qualifying.