Brandon Nakashima rockets into Top 100 with summer hard-court surge

WATCH: Nakashima addresses the crowd following his runner-up finish in Atlanta.

It took Brandon Nakashima the first half of the season to climb more than 35 spots in the rankings, but now he's climbed more than 40 spots in just two weeks.

The 19-year-old is into the Top 100 for the first time this week at No. 89 following back-to-back ATP finals at Los Cabos and Atlanta.

"It feels pretty good, for me it’s quite an accomplishment," he told the ATP Tour website. "It gives me a lot of confidence coming into this hard-court swing. I’m looking to just build off of it and keep improving and keep getting better."

Nakashima is now aiming to win his first ATP title and move further up the rankings. It's a big turnaround from going 4-7 during the clay events, which followed what had been a good start to the season.

"It hasn’t been easy," he said. "Having that slow clay-court swing, not winning too many matches in Europe, and then having the hard courts and try to gain some momentum and show that I belong with these guys and that I can play on the ATP Tour."

It's a sign that he's improved his mentally, which he says has been the biggest impetus behind his upward movement this season.

"That has been the biggest thing for me, especially for my confidence. And then also the minor things, like the technique and my footwork on the court I think has definitely improved," he said.

Nakashima is playing as a wildcard at the Citi Open, this week's ATP event at Washington.