MELBOURNE, Australia - No.14 seed Sofia Kenin soared to her first Grand Slam title, rallying from a set down to defeat former World No.1 Garbiñe Muguruza, 4-6, 6-2, 6-2 to win the Australian Open - becoming the youngest American since Serena Williams in 2002 to capture a major crown.

GALLERY: Story of the Final - Best images from Sofia Kenin's Australian Open triumph

"My dream has officially come true," Kenin said during the trophy ceremony. "If you have a dream, go for it, because it can come true."

At 21 years of age, Kenin shook off early jitters to play phenomenal tennis in the biggest match of her young career, clinching the victory after two hours and three minutes on Rod Laver Arena. "This is such an honor," she said afterwards. "I'm so proud of myself, my dad, my team, everyone that has been around me. We've all worked hard. We've been through tough times. We did it. We fought. I'm just on cloud nine."

Muguruza was the more experienced player coming into the match, playing her fourth Grand Slam final - though her first since winning Wimbledon in 2017 - and aiming to be the first unseeded player to win the Australian Open since Serena Williams in 2007. Starting the season with a return to former coach and 2020 Hall of Fame Inductee Conchita Martinez, the two-time major champion pulled out of the Hobart International with a viral illness and lost the first six games of the fortnight to Shelby Rogers in the first round. Once she dug out of that she showed the form that has already taken her to two major titles, upsetting the likes of Elina Svitolina, Kiki Bertens, and fellow former No.1 Simona Halep in a thrilling semifinal.

Where Muguruza's Melbourne surge has been a return to form, Kenin (who goes by 'Sonya') has been on a steady rise since reaching the third round of the 2017 US Open, shocking Serena Williams' at last year's French Open and winning her first three WTA titles on two different surfaces. Her run to the final was highlighted by a decisive win over World No.1 Ashleigh Barty - her second over the reigning Roland Garros champion in six months. 

The pair played just once before, with Kenin - fresh off a title run at the Guangzhou International Women's Open - winning a China Open three-setter that was full of momentum shifts.

Some of that was on display early in the opening set, though this time it was the 26-year-old Muguruza who struck first, breaking in a long third game on her third opportunity.

Kenin, who was born in Moscow before emigrating to the United States not long after her birth, risked becoming overawed in her first Grand Slam final when she fell behind 0-40 at 2-4, but saved four break points - two with searing backhand winners - and capitalized on a flat game from the Spaniard to draw level at four games apiece. 

Muguruza soon steadied and engineered two more break points by getting low to swipe an inside-in forehand winner, and served out the set with an enthusiastic celebration.

"I was obviously devastated," recalled Kenin of losing the first set. "I knew I didn't take my chances. Of course, she played some really good tennis. I'm playing a two-time Grand Slam champion. She's had so much experience. I knew I needed to somehow forget what happened, just move forward and just keep believing in myself."

The second set saw the American rebound in style, surging ahead 5-2 with some flawless hitting and earning her first set point with a backhand return winner. Forcing a backhand long from Muguruza, the youngster leveled the final.

Getting advice from the trainer between sets, Muguruza's movement appeared hampered at moments but stayed with Kenin through the first four games, putting away an overhead to dig out of a service game where she trailed 15-30.

"I'm not very happy about my performance. I think I had to play better today because she came up with a great level. I think at the important moments I didn't find my shots. I think she found her shots," Muguruza said after the match.

"I did feel a little bit of lack of energy after so many matches. Physically, it was a tough battle out there, so it's just a tough moment.

"I think the way she handled the break points and the game points, these kind of moments, I think she came out doing winners, which is a tough moment. I think she played very well. I think it's her first Grand Slam final for her and she performed really well."

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A netted forehand from Kenin handed the Spaniard three break points in the following game, but she responded with aplomb, saving all three with winners. An ace and a forehand pass ended what became the match's defining game as she closed in on Grand Slam glory.

"I can remember that game very well, yes," Kenin continued. "That's the game I feel like changed things. I had to play some best tennis. I did. After that, I was on fire. I was ready to take the beautiful trophy.

"I knew I had to take my chance. I had to be brave by playing a two-time Grand Slam champion. All respect to her. She played a really tough match. Every point, it was such a battle. A lot of moving. A lot of emotions on court from both sides.

"I knew I needed to come up with the best shot, five best shots of my life...It got me to win a Grand Slam."

While Muguruza came out on top of a 19-shot rally, Kenin kept pressing, forcing a volley miss from the unseeded Spaniard to earn a break point, which she converted off a double fault.

Serving to stay in the final, Muguruza put down two aces but more double faults kept Kenin in contention, and one last double fault - her eighth in total - secured victory for the American on her second championship point.

In all, it was a stunning match from Kenin, who struck 28 winners to 23 unforced errors and converted an impressive five of six break point opportunities. Muguruza struck four more winners, but ended the match with 45 unforced errors - 17 in the final set - as the American's relentless accuracy proved too strong.

Already set to crack the Top 10 by reaching the final, Kenin will rise to a career-high ranking of No.7 in next week's rankings.

2020 Australian Open Highlights: Kenin seals first Grand Slam with win over Muguruza