NEW YORK—The first day of play at the U.S. Open's new Grandstand court has seen some entertaining matches, with the court getting a thumbs up from the participants.

"It's definitely a big upgrade," said Caroline Wozniacki, who defeated Taylor Townsend in three sets to open the stadium.

Though describing herself as a fan of the former version of the court, famous for producing thrillers at Flushing Meadows, Wozniacki said this Grandstand also looked set for "a lot of special matches."

Even in defeat, Townsend shared Wozniacki’s positive sentiments.

“It's beautiful. I didn't realize how big it was until people started to come in and started to get a little bit more packed,” said Townsend. “You know, people started cheering. I was in awe.”

Another long match followed on Grandstand as John Isner defeated Frances Tiafoe in five sets in front of another packed crowd. "It's going to be one of the best courts at the U.S. Open," said Tiafoe in a courtside interview with ESPN.

Isner, who described playing on the Grandstand as a "pleasure," said he would like to play his next match on the same court.