As soon as the last Vikings fans stumbled out of U.S. Bank Stadium on Sunday evening, still reveling in their team's improbable last-second victory over the New Orleans Saints, the major work began getting the stadium ready for its next close-up.

With less than three weeks to go before Super Bowl LII, the clock is ticking to transform the stadium. A lengthy to-do list awaits: End zones have to be repainted, coat racks installed and space added to accommodate the media crush.

"Some of that work was important to get moving on quickly," said Peter O'Reilly, senior vice president of events for the NFL, which officially took over the stadium on Sunday after the game.

About 11 p.m. Sunday, workers marched onto the field and began peeling the purple turf from the end zones; it will be replaced with the still-to-be-determined colors of the NFC and AFC champions. Also gone, at least temporarily, is the Vikings Norseman insignia at midfield, to make room for the Super Bowl logo. NFL-sponsored branding will start appearing throughout the stadium.

Crews worked in below-zero temperatures installing a 50-by-100-foot electronic screen on the giant glass doors, which will be used to display promotional images leading up to the game.

Shifting schedules

Originally, the league was scheduled to take over the stadium Jan. 2, but the Vikings' extended playoff run delayed that two weeks.

Some local officials admitted privately that they were relieved when Falcons quarterback Matt Ryan's 4th-and-goal pass fell incomplete in the waning moments of their divisional game against the top-seeded Philadelphia Eagles. Had the Falcons won, Minnesota — the NFC's No. 2 seed — would have hosted this week's conference championship, delaying the stadium changeover until this Sunday.

Staging a Super Bowl in an urban setting adds an extra layer of complexity. Traffic congestion can add to work delays. And unlike in Houston, where the NFL used the vacant Astrodome for storage, extra space is more difficult to come by.

The region's harsh winters were also a consideration, although Mike Howard, a spokesman for the state Super Bowl Host Committee, said that organizers caught a break with milder-than-normal temperatures, allowing work to stay on schedule.

But NFL officials insisted that, after months of advance planning — with the Host Committee, stadium operator SMG, the Vikings and the league's architect, Kansas City-based Populous — they were prepared for any potential glitch.

"We were prepared for either scenario and were just waiting to see which way it went," said O'Reilly, pointing out that Sunday's game was the first time that a Super Bowl stadium had ever hosted a divisional playoff game in the same year. "We were confident either way."

Last year, the Houston Texans were a wild-card team, meaning that even though they played, and won, their first playoff game at home, theoretically they wouldn't play at NRG Stadium again unless they advanced to the Super Bowl — they lost in the divisional round to the eventual champion, New England. As such, delays in Super Bowl preparations were minimal.

Still, O'Reilly conceded that a Vikings home game Sunday "would have really compacted the time period significantly, which would have certainly meant bringing more resources to bear."

By Tuesday morning, a large white and purple canopy had sprouted in the park outside the stadium, which will be closed to the public until after the game, while vehicles buzzed around the stadium, hauling equipment back and forth from what resembled a giant Erector Set shelf.

Inside, workers in white helmets were busy with other tasks, including removing some seats.

Paring seats, adding press

The $1.1 billion stadium seats 66,200 for a normal Vikings game, but the NFL expects to drop its capacity to 65,000 for the Super Bowl to free up space for the colossal media, security and entertainment presence at the event, as well as additional luxury areas.

With the stadium's regular press area able to hold only 250 people, the NFL will add space to accommodate the record 5,800-plus credentialed journalists from U.S. and international news outlets expected at the game. Work is underway on an auxiliary press box, as well as broadcast booths in the main concourse for foreign TV media.

In addition, workers last week started assembling a large metallic gate at the western edge of Commons Park, which visitors will use to reach the stadium. The roughly 2½-block security perimeter that will be in place a few days before the game also started to take shape, as crews placed chain-link fencing on concrete slabs along nearby streets.

O'Reilly said that the changeover will involve between 500 and 600 workers.

Meanwhile, representatives from the four remaining playoff teams — Philadelphia, the Vikings' opponent on Sunday, Jacksonville and New England — were in town for customary meetings on Monday and Tuesday, O'Reilly said, to arrange such logistics as team hotels and training facilities, before taking a tour of the year-and-a-half-old stadium.