The most inexperienced players also looked the most comfortable in the first week of the U.S. Open.

Starting in the qualifying draw, Emma Raducanu of Britain has won all seven of her matches in straight sets, without needing a tiebreaker in any of them. Her most recent wins have been her most emphatic. She beat 41st-ranked Sara Sorribes Tormo of Spain, 6-0, 6-1 on Saturday to reach the round of 16. On Monday, Raducanu routed the 43rd-ranked American Shelby Rogers, 6-2, 6-1.