Brandon Nakashima became the first American winner of the ATP Next Gen Finals with a straight-sets victory over Jiri Lehecka on Saturday.

The 21-year-old was beaten by Sebastian Korda in last year's semi-finals, but he more than made amends by winning all five matches in Milan en route to the title.

Lehecka was also defeated in straight sets by Nakashima in the group stage, but he broke his opponent in the opening game of the final at the Allianz Cloud.

Nakashima recovered from 3-1 down in a first set that went the distance and managed to get over the line after a 5-0 lead in the tie-break was reduced to 6-5.

Czech youngster Lehecka wasted a glorious chance to level up the contest when letting two set points pass him by in the second-set tie-break, which Nakashima went on to win.

The match was over inside 80 minutes as Nakashima, who struck 21 winners to Lehecka's 27, served out the final set to win 4-3 (7-5) 4-3 (8-6) 4-2.

"I am super happy right now," Nakashima said at his on-court interview. "It was a great tournament, this whole week.

"This final was another tough match. Just a few points that could have gone either way. I am happy with my level today. It's a good way to finish off the year.

"It was a final so there are going to be some pressure moments. There were some nerves at the beginning, but I'm happy I was able to turn it around quickly and close it out."