Local favorite Kei Nishikori fell short in his bid for a third Japan Open title on Sunday, losing the final to unseeded Russian Daniil Medvedev in a straight-sets upset.

The 6-2, 6-4 defeat in front of a stunned home crowd at Musashino Forest Sports Plaza came after the third-seeded Nishikori had reached the tournament decider without dropping a set.

After putting on a serving clinic in his semifinal against France's Richard Gasquet the previous day, world No. 12 Nishikori was broken three times by the 32nd-ranked Medvedev, who claimed his third career title with the win.

Accepting the winner's check and trophy, an elated Medvedev lauded both his opponent and fans at the newly completed venue for the 2020 Tokyo Olympic Games.

"(You) are maybe the best fans in the world. You make this stadium cool every day," the 22-year-old Medvedev said.

"I would like to thank Kei, of course. He is a great champion and one of the best players in our sport."

Electing to receive, Nishikori went on the attack in the opening game as Medvedev struggled to find the mark with his serve. Nishikori earned break point with a forehand winner, but Medvedev went on to hold despite four faults.

It was the two-time champion who failed to hold first, however, conceding a love game in the fourth after losing a rally on his second serve at 0-40.

The break was bookended by love games in the third and fifth for Medvedev, who raced to a 4-1 lead after overcoming his early service woes.

Nishikori held in the sixth, but an increasingly confident Medvedev blasted a pair of aces exceeding 195 kilometers per hour as he extended to 5-2 with another love game.

With his own serve faltering, Nishikori gave Medvedev two set points in the eighth, defending the first but conceding the break and the set with a double fault at 30-40.

Medvedev opened the second set in imposing fashion, denying Nishikori a single return in play for another love service game and a 1-0 lead.

Forced to defend another break point in the fourth game, Nishikori faulted at 30-40 before holding serve to level at 2-2, winning the advantage with a 185-kph ace.

With his radar locked in, Medvedev served back-to-back aces at 15-15 and 30-15 in the following game to take a 3-2 lead over the semifinalist at last month's U.S. Open.

The pair continued to trade service games until the tenth, when Nishikori faltered to give Medvedev two match points.

Faulting at 15-40, Nishikori put his second serve in play but mishit his first groundstroke of the subsequent rally, sending an attempted forehand winner high into the air and out.

The 28-year-old Nishikori had been seeking to join Pete Sampras as a three-time winner of the tournament. Only Stefan Edberg, with four, has won more championships in Tokyo.

Earlier in the day, Ben McLachlan followed up his recent Davis Cup success for Japan by winning the men's doubles final alongside partner Jan-Lennard Struff of Germany.

The fourth-seeded pair defeated Russia's Raven Klaasen and New Zealand's Michael Venus 6-4, 7-5, taking the match in 1 hour, 23 minutes without surrendering a break.

McLachlan, who captured the Shenzhen Open doubles title last weekend, has now won three tour championships. His first was at last year's Japan Open, which he won with Japan Davis Cup doubles partner Yasutaka Uchiyama.