Some top male players -
including Roger Federer
- have complained that the tournament, held in New York, was the sport's only major that held the semi-finals and final on consecutive days.
Williams revels in 15th slam title
US Open men's champion Andy Murray said he was pleased organisers had taken on board the players' concerns, while 2012 women's champion Serena Williams believed the changes would make the tournament "stronger than it's ever been for all players".
Widmaier added: "The day of rest is being embraced across the board.
"Because of the nature of the game, and to assure a final that can be played at the highest competitive level, you need an extra day of rest. We recognised that."
the men's final will be played on Monday, 9 September, with the men's singles semi-finals on Saturday, 7 September.
The women's singles semi-finals remain unchanged and will be played on Friday, 6 September while the women's final will take place on Sunday, 8 September.
The USTA also announced that total prize money in 2013 will increase by $4m (£2.4m) to a record $29.5m (£17.9m), the largest in the tournament's history.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.