Talk of ‘fake bubble,’ ‘bubble in bubble’ on the U.S. Open’s Day 1

A member of the USTA crew watches a match during the first round of the U.S. Open tennis championships, Monday, Aug. 31, 2020, in New York. (AP Photo/Frank Franklin II)

NEW YORK — For all of the obvious concessions to the coronavirus at the no-fans-allowed U.S. Open — near-empty arenas; silence pierced by the occasional clap, sneaker squeak or roaring jet; a lack of line judges — the aftereffects of one player’s positive test caused the biggest stir on Day 1.