MORE IN SPORTS: Long lines, long wait times sour Day 1 for fans of U.S. Open,

The issue wasn’t having enough fans to attend the US Open in a pandemic. It was getting them inside that became “a s--- show.”

Fans complained of waiting up to 2 1/2 hours to get through security into the Billie Jean King National Tennis Center, with the line at the East Gate packing attendees all the way to the subway station by Citi Field.

“The optimal word is ‘s--- show,’” said one fan named James, who attended the opening day of the tournament with his wife, Susan, and was dismayed by the 75-minute wait after purchasing tickets for $480. “Look where my seats were. These are big time seats. I would never do this again.”

There were concerns that the last-minute requirement of vaccination proof would slow the process, but the USTA blamed it on fans arriving too late and with too many bags. Patrons at the East Gate said the vaccination portion was seamless, if not entirely trustworthy or thorough, as most were able to flash either a card or photo of a card without it being cross-checked with an ID.

“I think [Mayor de Blasio] should fine them,” Ed Greenberg said. “It was two hours and there was a mass of people. There was nobody directing which lines people should be on. We went on the proper line and it just became a crush of people.”

Another fan, Nicole, said she flew from Switzerland unvaccinated with her American passport on Thursday. A day later, the U.S. Open — as ordered by de Blasio amid a COVID spike — required proof that fans age 12 and older received at least one dose of the vaccine.