The United States Open, the annual end-of-summer tennis tournament in Flushing, New York, had not produced a first-time winner since 2009. 

Last night, Marin Cilic ended a streak of repeat winners by claiming his first career Grand Slam title in an unlikely matchup against Kei Nishikori in the final.

The 14th seeded Cilic is the lowest seed to have won a Grand Slam title since the unranked Gastón Gaudio won the 2004 French Open. 

Cilic breezed through the opening two rounds of the tournament in straight sets and needed a fourth set to secure his spot in the fourth round. 

Cilic squared off against Gilles Simon in the fourth round and defeated the Frenchmen in five sets for the first time in his career.

Entering the quarterfinals of the tournament, it appeared once again that one of tennis’ “Big Four”—Novak Djokovic, Roger Federer, Andy Murray and Rafael Nadal—would take home the title. 

The “Big Four” had taken the past four US Open titles before this year and nine of the last 10 dating back to Federer’s 2004 title. 

Of the four, only Nadal did not make it through to the quarterfinals, but he sat out of the tournament with a wrist injury and is generally the weakest of the four on the US Open’s hard court.

Cilic dispatched the No. 6 seed Tomáš Berdych in his quarterfinals match in a three set sweep to set up a semifinal match with Federer, who won five US Open titles in a row between 2004 and 2009. 

Federer, ranked second in the tournament, posed little challenge for the eventual champion, falling in straight sets, 6-3, 6-4, 6-4. 

The only thing more surprising than Cilic’s run to the final was his opponent—the 10th seeded Nishikori. 

Nishikori, much like Cilic, breezed through the opening three rounds of the tournament before needing a five-set victory in the fourth round. 

Unlike Cilic, however, Nishikori was matched against the tournament’s fifth seed, Milos Raonic. Nishikori edged his way past to Raonic secure his spot in the quarterfinals. 

Nishikori, the first Japanese player to ever reach a Grand Slam final, was dealt the toughest draw in the finals bracket of all quarterfinalists. Nishikori was scheduled to face the tournament’s third seed Stan Wawrinka and the winner of a match between Djokovic and Murray if he advanced past Wawrinka. 

Less than two days after needing five sets to upset Raonic, Nishikori pulled out another five-set stunner against Wawrinka. 

Nishikori needed four hours and 15 minutes to defeat Wawrinka 3-6, 7-5, 7-6 (7), 6-7 (5), 6-4. 

His reward was a semifinal date against Djokovic, the world’s top-ranked player.

Nishikori stunned Djokovic to set up the unlikely final against Cilic, but his luck would soon run out.

The finals matchup between ČCilicćand Nishikori was the first time since 1997 that the US Open final was between two players in their first finals appearance.

Cilic, still fresh from three-straight sweeps, outplayed Nishikori in a final that lasted just 1:54. Cilic was never truly challenged by Nishikori, earning his first US Open title by a score of 6-3, 6-3, 6-3. 

The champion won his final 10 sets of the tournament en route to three sweeps, including the final match against Nishikori.

“I think I enjoyed my best tennis ever here and played the best ever in my life,” Cilic said after the win.

Cilic pounded out 17 aces during the win, one that will earn him the ninth spot on the next Association of Tennis Professionals rankings.

 Cilic began the US Open at the No. 16 ranking.  

An unlikely final produced a first-time winner, a fitting end to an unpredictable tournament.