Big East champion St. John’s will have plenty of support on Thursday night when the Red Storm begins its quest to win the NCAA men’s national basketball championship. Meanwhile, nervous bookmakers are cringing at the possibility of such an outcome.

For much of the regular season, St. John’s was a long shot to capture the national title. Then the Red Storm caught fire and won nine straight games to claim the school’s first outright regular-season Big East title in 40 years and first tournament championship in 25 years.

Since the winning streak began in mid-February, St. John’s has gone from long odds to win the national championship to perhaps the hottest team entering March Madness. ESPN BET lists St. John’s as a 20-1 choice to win the national title. The Duke Blue Devils, a no. 1 seed for the 15th time in the program’s history,  are the favorite at +300, followed by Florida (+375), Auburn (+500), and Houston (+650).

An estimated $3.1 billion is expected to be legally wagered on this year’s men’s and women’s national tournaments. Most of the betting is conducted during the first four days of the tournaments, but those who placed a futures bet weeks or even months ago on St. John’s winning it all gained much more favorable odds, which is why bookmakers fear making huge payoffs should the Red Storm take the title. St. John’s (30-4) begins play against Omaha (22-12) at Providence.   

“We’re definitely rooting against St. John’s,” the sportsbook director at Atlantic City’s Borgata, Thomas Gable, told Yahoo Sports. “They’ve been extremely popular and we have a lot of liability on them. They were 50-1 [odds] through the vast majority of the season and 25-1 going into the conference tournament.”

Sportsbooks wouldn’t be on the hook nearly as much should one of the favorites win. “If Auburn or Florida wins, we’re in great shape,” Mr. Gable said. Auburn (28-5), Duke (31-3), Houston (30-4), and Florida (30-4) are the top seeds in each of the four regions.

According to ESPN, more bets have been placed on Duke than any other team, despite freshman sensation Cooper Flagg injuring his ankle last week in the ACC Tournament. “Cooper Flagg’s health is a question mark, but we expect action to pour in on Duke if Flagg can play,” Seamus Magee of BETMGM told Yahoo Sports.

In action involving the top seeds, Auburn plays Alabama State, a 70-68 First Four victor over St. Francis;  Florida plays Norfolk State, Houston meets SIU Edwardsville, and Duke plays the winner of Wednesday’s First Four game between American and Mount St. Mary’s. UConn, attempting to win a third straight NCAA title, plays Oklahoma.

St. John’s should benefit from its first two games at Providence. It represents a homecoming for the head coach, Rick Pitino. His Hall of Fame career took root in 1985 when he was named head coach at Providence College. Two years later the Friars were in the Final Four. Now, at age 72, the Big East Coach of the Year is taking his sixth different team to the NCAA Tournament and looking to become the first to coach four different teams to the Final Four. Around stints with the New York Knicks and Boston Celtics, he won national titles with Kentucky (1996) and Louisville (2013).

“This one of all of them means the most to me along with the Knicks,” Mr. Pitino said on “The Pat McAfee Show,” “because you’re doing it where you grew up eight streets from Madison Square Garden. This is your home. The people all talk like you. When I was in Louisville and Lexington, nobody sounded like me.”

St. John’s is an 18-point favorite to get past Omaha, which is making its first-ever trip to the NCAA Tournament. The Mavericks of the Summit League average 78 points per game. Senior forward Marquel Sutton averages 19.1 points and 8 rebounds per game. He totaled 28 points and 11 rebounds against Kansas City in the semifinal game of the Summit League Tournament.

The Mavericks are known for smashing trash cans after wins. It’s a tradition that began in December when an assistant coach kicked a can at halftime of a game Omaha rallied to win. After a 4-9 start, the Mavericks have won 18 of 21 games and have seen the demise of countless trash cans along the way.

“We have fun with it,” Omaha’s head coach, Chris Crutchfield, told ESPN. “We’re a young program in Division 1. This is our first time going to the NCAA Tournament. The national attention we did get from the trash can was fantastic. We needed something like that for our program and university. It happened organically and wound up going viral. It only happened because we won basketball games.”

If the no. 2 seed Red Storm gets past no. 15 Omaha, it faces the winner between no. 7 seed Kansas (21-12) and no. 10 Arkansas (20-13).  

South Carolina (+270), UConn (+280), UCLA (+500), Texas (+650), and USC (+700) are the favorites in the women’s tournament.