Both have improved substantially this season with their current teams, according to their childhood coaches, and each had a good showing in World TeamTennis play in recent weeks.
The 22-year-old Fritz was first coached by his father, Guy, and his mother, Kathy May, both former pros. Now ranked No. 24, he reached the Acapulco final just before the suspension of pro competition.
"He's slowly, steadily moving up. He's more professional now, he's been working harder, more consistently,” Guy Fritz told Tennis.com. “He's much fitter now, and that's starting to pay off.
"In a year and a half, he's had 10 wins against guys in the Top 10—he's beaten [Alexander] Zverev, he's beaten Dominic Thiem, he's beaten these guys."
A former top junior, Fritz has been coached by the experienced David Nainkin and Paul Annacone for a couple of years, and with his trainer and physio, has kept developing his game and fitness during the tour break.
"He's consistently serving in the 140s now, so it's one of the best in the world. The forehand's always been a major weapon for him. And when you're a pro you've got to have these two major weapons," said Guy Fritz, also identifying one area he wants improved. "His backhand is very solid. His net game's improving. But I'd like his return game just a little bit better.”
Another up-and-coming name from the area is 19-year-old Nakashima, who is based in San Diego, California. A famed local coach, Angel Lopez, taught him from seven to 14 years old.
"He came to me with a big racquet, I took him down to a small racquet, gave him some swings," Lopez told Tennis.com. “And Brandon, when he was a little guy, I gave him the whole game, no weaknesses."
"His temperament is solid—he doesn't celebrate, he doesn't get down.," Lopez said. "Fundamentals are solid. He knows where to be on the court. He can volley, he's got every shot in the book. Brandon's got a great return.”
Turning pro this season, Nakashima has brought on Dusan Vemic and Pat Cash as coaches, moving to No. 220 in the rankings.
"He's got a team now," Lopez said. "Big backhand, big serving now, he's got good speed. But he's got a good roadmap, he knows where to be. Brandon's all about getting better."
Lopez has coached for more than 40 years. While he says good coaching is important when developing a pro player, so is motivation—something Nakashima isn't lacking.
“You give them good fundamentals when they're young, and they have to have the desire. Brandon is totally focused on tennis,” Lopez said. “He's always about getting better every day. At 14, 15 Larry Stefanki helped him."
"And his attitude is just like [Rafael] Nadal," Lopez said.
His play this season has got him a wildcard into the US Open. Fritz is scheduled to return at the relocated ATP Masters at Cincinnati.