Roof closed, case closed for the United States Tennis Association.

After more than a decade of planning and three years of construction, the USTA on Tuesday ceremonially closed the $150-million roof over Arthur Ashe Stadium. When Jeanne Moutoussamy-Ashe, the late champion’s wife, pushed the button, the two 1 million-pound panels came together in about six minutes, the culmination of countless thousands of hours of concept, design and building that officially began in 2013 but had been hashed over, studied and restudied since the turn of the century.

“We said back [in 2013] that we would make the impossible possible and today we have,” said Gordon Smith, executive director and chief operating officer of the USTA. “We said we would not do this on the backs of our fans. We said we would self-fund this 100 percent, and we have.”

The roof might be the least of the wow factor at the Open this year, what with much of its superstructure in place during last year’s Open.

As a big part of the USTA’s announcement in 2013, it also said it was reinventing the whole campus and will have much of that work done before the Open begins Aug. 29. The new Grandstand, with 8,125 seats, debuts in the southwest corner of the property and most of the field courts and their seating, from No. 7 through 16, have been replaced. There is a wider spectator boulevard to allow easier access throughout that part of the grounds. And a second food court was added outside the new Grandstand.

As for shade, a frequent spectator complaint over the years, more than 100 trees have been imported and the superstructures of the new Grandstand and the other field courts will provide much needed relief from the sun.

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After this Open, Louis Armstrong Stadium and the old grandstand will be torn down and replaced with a new 14,000-seat roofed stadium, still to be named and scheduled to open in 2018. That last phase of the National Tennis Center’s $500-million makeover will be complete 41 years after it opened and 21 years after its first reinvention with the opening of Ashe Stadium in 1997.

But on Tuesday the Arthur Ashe roof took center stage, a roof that will pretty much guarantee a Sunday finish for the Open in perpetuity. The Open had been plagued with rain-delayed Monday finishes, forcing it to schedule in advance Monday finishes in the 2013 and 2014 tournaments. Rainouts in Ashe caused a huge amount of ticket refunding and television complications. Now, in the case of rain, all matches can be completed on Ashe. The USTA would be responsible for refunds on the outer courts, a significantly less financial hit.

As Katrina Adams, the chairman of the USTA and its president stood to speak, she held out her hand as if feeling for raindrops.

“Is it going to rain?” she said with a wry smile. “It doesn’t matter anymore.”

After the closure, it was Billie Jean King’s turn to push the button to open it again. It didn’t work. It didn’t work a second time. But the technicians sorted it out, the huge panels parted, and the centerpiece of the U.S. Open’s future had made its mark.