The Vikings and the state took control of the new U.S. Bank Stadium from Mortenson Construction Friday, receiving an oversized, commemorative black key with the city skyline carved out and the date engraved.

"Let's play football!" said John Wood, Mortenson senior vice president, as he handed over the key. The stadium is "essentially done" and ready for the move-in to get started, he said.

While football games won't happen for a couple of months, the ceremony marked what is officially referred to in the construction industry as ­"substantial completion."

The milestone moment came 45 days ahead of deadline and 30 months after construction began. The jagged, 270-foot-high glass and steel building will seat 66,200 fans and play host to the 2018 Super Bowl. The $1.1 billion public-private project rose on the site of the Metrodome, which came down in January 2014.

The handoff means that at 12:01 a.m. Saturday, the Minnesota Sports Facilities Authority (MSFA) takes responsibility for operating costs, such as the water, electric and 24-hour security bills. MSFA, Mortenson and the Vikings will continue to work through inspections and to identify items that must be fixed or adjusted.

The formal ribbon-cutting will take place July 22 with a free public open house on the two following days.

The Vikings play in the stadium for the first time on Aug. 28 with a preseason game at noon against the San Diego Chargers, but the true inauguration will occur at 7:30 p.m. on Sunday, Sept. 28, against the Green Bay Packers. The first event is a soccer match Aug. 3.

MSFA will move in much sooner. Chairwoman Michele Kelm-Helgen said its next monthly meeting, July 15, will be in the new offices.

Now that MSFA, which represents the public, has control of the building, training of staff in all areas can begin on-site, Kelm-Helgen said. The building's operators have already conducted job fairs to hire workers for everything from security to tour guides, bartenders and cleaners.

Wood said the early completion provides time before the first event "to get that building absolutely immaculate."

Remediation already is complete on the most substantial snag on the project: moisture seeping through an outer wall near the roof. Mortenson covered the estimated $4 million cost of the fix that Wood said has been made.

The handoff also triggers a 21-day countdown for Mortenson to decide whether to accept $16.25 million put into escrow for higher construction costs related to design changes. Those costs were once projected to be as high as $30 million.

In February, Mortenson, MSFA and Dallas-based HKS Architects reached the agreement for the escrow account. If over the next 21 days Mortenson rejects the money, the matter would proceed to binding arbitration.

Wood said there is a "very high likelihood" the company would agree to the amount.

As he, Kelm-Helgen and Vikings Chief Operating Officer Kevin Warren took reporters' questions Friday, the mood was purely celebratory.

"Players are excited. Staff is excited. Our owners are excited," Warren said.

In other action at the meeting, Kelm-Helgen delayed again an announcement on a bird-safety study.

At last month's meeting in May, she had said she would have an announcement in June. On Friday, she said that she will have an announcement in July about a study to determine whether the building is deadly to birds.

Activists have repeatedly asked MSFA to take steps to ensure the glassy building doesn't become a death trap for birds colliding into reflections. This time, preservationist Ann Laughlin asked Kelm-Helgen that the study have clearly defined parameters and that the process and the results be open to the public.

Those who want to get into the stadium for self-guided tours in late July must acquire free tickets through Ticketmaster online or by calling 1-800-745-3000.

Twitter: @rochelleolson