Pegula cited the move by the US Tennis Association — which followed the French Tennis Federation's decision to begin on Sunday in 2006, and the Australian Open's move to do the same in 2024 — as an example of her sport's repeated failure to ask for, or follow up on, athletes' input. Wimbledon is now the lone major that starts on Monday.

"A lot of times, they ask for player feedback, and, when we do (respond), they don't listen to anything we say," said Pegula, one of 20 players who signed a letter in March addressed to the people who run the Grand Slam events to ask for better communication, more contributions to player welfare and a higher share of revenue. "The way they go about announcing these things, sometimes players aren't aware."

This also comes at a time that players have complained about the recent shift to longer non-Slam tournaments that last more than a week.

Those in charge of tennis point to higher prize money that comes from those extended tournaments — and changes, such as the extra day, have coincided with increases in prize money, which is up to a record $85 million, including $5 million to each singles champion, at the US Open.