Nineteen-year-old American Brandon Nakashima picked up one of the biggest wins of his young career by upsetting top seed and 84th-ranked Thiago Monteiro (Brazil) 6-4, 6-3 Thursday in the second round of the 2020 Orlando Open presented by Nemours. He was one of four Americans moving through to the quarterfinals on the day, which guarantees at least one American finalist at the ATP Challenger 80 event.

Nakashima used a sturdy service performance, backed up by one break in each set, to propel him to victory. He served up a total of eight aces and won 71% of the points played on his first serve; additionally, Nakashima saved all four break points he faced. The defeat of Monteiro marks the fifth top-100 triumph in 2020 for Nakashima.

No. 8 seed Mackenzie McDonald was the only other seed in action Thursday, facing off with Sweden’s Elias Ymer. The American would keep Ymer under pressure on nearly every service game, securing four breaks en route to a 6-3, 6-3 result in his favor.

The other two quarterfinals pitted two Americans against each other. Qualifier Alexander Ritschard won his fourth match on the week with a 6-3, 6-4 defeat of lucky loser Nick Chappell and Mitchell Krueger rallied past Bjorn Fratangelo 3-6, 6-2, 6-2.

In doubles, the No. 1 and No. 2 seeds are through to the semifinals after winning on Thursday. Top-seeded Hans Hach Verdugo and Miguel Angel Reyes-Varela, both of Mexico, knocked off Taiwan’s Chun-hsin Tseng and Tung-Lin Wu 6-3, 6-4; the second-seeded pairing of Andrey Golubev and Aleksandr Nedovyesov representing Kazakhstan shook off a slow start to down Peter Polansky (Canada) and Dmitry Popko (Kazakhstan) 2-6, 6-4, 10-5.

Awaiting the top seeds in the final four will be American tandem Krueger and Jackson Withrow, who bested Treat Huey (Philippines) and Martin Redlicki (USA) 6-3, 6-2. Frenchmen Sadio Doumbia and Fabien Reboul are set to be across the net from the No. 2 seeds after taking care of Daniel Elahi Galan (Colombia) and Christian Harrison (USA) 6-4, 6-4.

Friday’s schedule of play, slated to get underway at 10 a.m., will feature all singles quarterfinal matchups along with the two doubles semifinals.

The 2020 Orlando Open is closed to the public; only credentialed guests will be able to access the tournament area. For more information on the 2020 Orlando Open presented by Nemours, including the daily order of play and live streaming links, click here.