LAS VEGAS -- The Seattle Seahawks opened as Super Bowl favorites over the New England Patriots, but the point spread was on the move Sunday night.

The Seahawks opened as 2.5-point favorites at multiple Las Vegas sportsbooks, but the number was down to a pick 'em at the Westgate Superbook and the William Hill and Wynn sportsbooks within an hour after opening. CG Technology was holding at Seattle minus-1. The MGM had the Patriots as 1-point favorites.

The Seahawks opened as 2.5-point favorites for the 2015 Super Bowl against the Patriots, but that line was on the move with kickoff still two weeks away. Joe Nicholson/USA TODAY Sports

There will be two weeks' worth of bets to shape what will be a highly anticipated Super Bowl on Feb. 1, in Glendale, Arizona. The Super Bowl point spread has never kicked off at a pick 'em.

Seattle advanced to its second straight Super Bowl with a remarkable 28-22 comeback win over the Green Bay Packers in overtime.

The Patriots had a much easier time, blowing out the Indianapolis Colts 45-7 in the AFC Championship Game.

This will be the sixth Super Bowl appearance for the Patriots under coach Bill Belichick and quarterback Tom Brady.

The MGM took a six-figure wager on New England minus-1 on Sunday night, according to vice president of race and sports Jay Rood.

More from ESPN.com For full betting coverage and expert Vegas analysis of the 2015 Super Bowl between the Seahawks and Patriots, check out ESPN Chalk.

Championship Sunday opened with a wild finish between the Seahawks and Packers. The money line odds at William Hill's live betting changed 291 times during the game. Trailing 19-7 with five minutes to play, Seattle was a 30-1 underdog to comeback to win the game after Seahawks quarterback Russell Wilson threw his fourth interception with 5:13 to play.

William Hill took three bets on the Seahawks at 30-1, the largest a $200 wager that paid $6,000, book spokesman Michael Grodsky told ESPN.

Seattle's miraculous comeback was a killer for the MGM sportsbook. In the final hour before kickoff, the MGM took a six-figure bet on the Packers plus-8.5; a six-figure bet on over 44.5; a six-figure bet on the Seattle money line, and a six-figure teaser bet on Green Bay and the over. They all cashed.

"Very brutal," Rood said.

The Super Bowl over/under total opened at 48.5 at most shops and was sitting at 49 as of Sunday evening.