The third time was the charm for the new retractable roof over Arthur Ashe Stadium.

The U.S. Tennis Association unveiled the $150 million roof over the centerpiece court at the USTA Billie Jean King National Tennis Center on Tuesday — after some glitches.

The roof closed with ease in its first official demonstration, but tennis legend Billie Jean King tried multiple times to open it with the push of a button. Her third attempt succeeded.

Matt Rossetti, president of the architectural firm that drew up the roof plan, said the issue “could happen” at the upcoming U.S. Open but a team of engineers would be on hand to fix it if necessary.

The roof, which is the size of 17 Olympic swimming pools, will be ready when the U.S Open begins on Aug. 29. The men’s final was delayed a day until Monday because of rain for five straight years from 2008-12.

USTA officials had long maintained that adding a roof over Ashe wasn’t feasible. But in 2013, Rossetti created a plan and the roof was added over two years.

“Here at the Billie Jean Tennis Center, we are making the impossible happen,” USTA executive director Gordon Smith said.

Moving at a top speed of 25 feet per minute, the roof over the 23,771-capacity stadium is built to close or open in under seven minutes. Twenty-two tennis courts could fit inside the 62,500 square-foot roof opening.

There are already retractable roofs over the main stadiums at the sites of two other Grand Slam tournaments, Wimbledon and the Australian Open. French Open organizers also plan to add one.

The Ashe roof is expected to be used only for rain, unlike the Australian Open, which also closes its roof in cases of extreme heat. The Chase name and logo will be on both the north and south sides of the roof for the U.S. Open.

Ashe’s retractable roof features two panels atop a 6,500-ton steel superstructure and is covered to provide shade for the spectators. Some 360 LED sports lights will illuminate the roof and stadium when closed. To control humidity inside the stadium when the roof is closed, a chilled water ventilation system was installed.

The U.S. Open roof is part of a $500 million-plus renovation paid for by the USTA. The renovation included adding new courts.