The opening for opportunity for men at the United States Open appeared to be, as it often is, in the one quarter of the draw without any of the Big Three — Novak Djokovic, Rafael Nadal and Roger Federer.

The gap in that relatively barren quarter of the draw is much wider after the first-round losses on Tuesday of all three top-10 players placed there.

The fourth-seeded Dominic Thiem bowed out in four sets, falling 6-4, 3-6, 6-3, 6-2 to 87th-ranked Thomas Fabbiano of Italy in Arthur Ashe Stadium. The eighth-seeded Stefanos Tsitsipas also lost in four sets to the in-form Andrey Rublev , a 43rd-ranked Russian who defeated Federer at the Cincinnati Masters this month. The No. 10 seed, Roberto Bautista Agut, who was the lone non-Big Three semifinalist at Wimbledon this year, lost in five sets to the 47th-ranked Mikhail Kukushkin of Kazakhstan .

Bautista’s exit may have been the most surprising. He has been one of the steadiest players of this year, particularly on hard courts, earning two wins over the top-ranked Djokovic. Bautista, 31, is at an age when players seem to reliably perform at or near expectations in Grand Slams. For the younger generation, that has been a considerable challenge.