Sloane Stephens felt her first time warp in Washington, DC.
Playing her first match with the new 25-second serving clock rule, Stephens sped back from a 2-5 deficit fighting off four set points to defeat compatriot Bethanie Mattek-Sands, 7-5, 6-4, at the Citi Open.
Watch: Players React To Serving Clock
Stephens said her initial experience with the serving clock was "a little weird" and led the US Open champion to conclude managing ticking time is a mind game.
"It's a little weird," Stephens told the media in Washington, DC. "You have to pay attention. But overall it wasn't too bad.
"But I definitely think in a match that's a little bit closer if you're like battling and it's six-all in the third set you're not going to be wanting to look at the clock."
The US Open will become the first Grand Slam tournament to use the 25-second serving clock in main-draw matches this month.
Players have 25 seconds from the end of a point before starting their service motion to begin the next point.
The chair umpire has discretion to pause the clock or reset it to 25 seconds. The clock begins ticking once the chair umpire announces the score following the previous point.
Stephens says it takes time to adjust to passing time.
"It is what it is and you can't change the rule now," Stephens said. "So we'll just see how it goes for the next couple of weeks leading into the US Open and hopefully everyone adjusts to it well."
Photo credit: Miami Open Facebook