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Victory also earned Alcaraz revenge for a stunning loss to Fritz at the Laver Cup team event in San Francisco this month, the Spaniard's first defeat by the American in four clashes, which came shortly after his triumphant U.S. Open campaign.

The 22 year-old had endured a scare after jarring his foot on his Tokyo debut last week, but was beaming as he celebrated his 67th match win this season and 24th tour-level title overall.

"It's been a pleasure to be able to play here in Tokyo in front of Japanese fans. I've enjoyed every single second I was on the court (apart from) the five minutes I was on the floor after I hurt my ankle," Alcaraz joked.

"I'm really happy with the level that I played and with everything. Starting the week not really good with the ankle, and the way that I came back from that and played a great tournament, great matches."

After a high-quality startto the match under the roof of the Ariake Colosseum, Alcaraz edged ahead when Fritz sent his shot long to drop serve for the first time, and the top seed was in no mood to relent as he went on to seal the opening set.

Fritz received treatment for a thigh problem before the start of the next set and Alcaraz immediately heaped pressure on the second seed by hitting a blistering forehand to break in the opening game.

The six-times Grand Slam champion quickly built a 4-1 lead, prompting Fritz to throw his racket to the floor in frustration, and although Alcaraz briefly wobbled on serve later, he secured the win with a delicate drop shot for his first Tokyo title.

"It's been great, my best season so far without a doubt," said Alcaraz, who defended his French Open title and reached the final Wimbledon final which he lost to Jannik Sinner.

His only other final loss this year came in Barcelona, where he was beaten by Dane Holger Rune.

"I didn't start the year that good, struggling emotionally, so looking back and how I came back from that, I'm just proud of myself, and of all the people around me who have helped me to be in this position," Alcaraz said.