Tennis is back in the Big Apple.

The US Open, one of the biggest sporting events in the world, starts Monday in Queens. The Billie Jean King National Tennis Center in Flushing Meadows Corona Park will host the event, which is expected to draw hundreds of thousands of fans.

Last year, all attendees were required to be vaccinated against COVID-19. This year, there are no vaccination requirements — however, there are exceptions for non-U.S. citizens traveling from abroad.

"We are on track to break every record from 2019," Danny Zausner, the COO of the USTA Billie Jean King National Tennis Center, said Sunday morning on NY1. "We are in a really good space as we get ready for the main draw."

Former world No. 1 tennis player and 21-time major champion Novak Djokovic withdrew from the US Open Thursday morning. The 35-year-old Serbian is unvaccinated and was unable to travel to the United States.

"He is an unbelievable champion," Zausner said. "We would love to see playing out here."

While Djokovic will not be present this week in Queens, Serena Williams will. The 23-time Grand Slam champion announced in a Vogue essay earlier this month that she will soon be stepping away from the game.

She will play Danka Kovinic in the first round on Monday at 7 p.m. With a loss, an iconic singles career for Williams could be over.

"We knew that she couldn't play forever as much as we'd love to see her do that," Zausner said.

This year’s US Open comes during the 25th anniversary of the world’s largest tennis venue, Arthur Ashe Stadium. The approximately 23,000-seat arena is the main stadium of the annual tournament.