WASHINGTON — Alex de Minaur held off a spirited run from 17-year-old countryman Cruz Hewitt in an emotional all-Australian showdown Thursday at the Mubadala Citi DC Open, one of four second-round matches at the William H.G. FitzGerald Tennis Center that shaped the quarterfinal field on both sides of the draw.

De Minaur beat Hewitt 6-2, 6-3 in 61 minutes on Stadium Court, needing that long to see off the wild-card qualifier who is the son of Hall of Famer Lleyton Hewitt. The two have known each other for years — de Minaur traveled the tour alongside a young Hewitt and his father — and the match ended with a long embrace at net as Lleyton watched from the stands in the pair’s first official ATP meeting. Second-seeded Ben Shelton fed off a raucous home crowd to rally past France’s Ugo Humbert 6-7 (3), 6-3, 6-4, surviving a tiebreak loss in the opener before winning 70.4 percent of his service points the rest of the way. Shelton was broken just once in six chances and closed it out with a string of highlight-reel winners that had FitzGerald Tennis Center roaring into the night.

On the women’s side, Jessica Pegula needed a third-set reset to get past Poland’s Magdalena Frech, dropping the opener 3-6 before winning 12 of the final 15 games in a 3-6, 6-3, 6-0 turnaround that sends her into a quarterfinal rematch with Anna Kalinskaya. Elina Svitolina also advanced, outlasting Polina Kudermetova 7-6 (4), 6-4 in an hour and 27 minutes, saving three break points in the second set before setting up a quarterfinal against Alexandra Eala.

The results push the Mubadala Citi DC Open into its quarterfinal round Friday at Rock Creek Park, with de Minaur, Shelton, Pegula and Svitolina all back in action as the tournament moves toward Saturday’s semifinals and Sunday’s championship matches.