The St. Louis Blues completed a massive mid-season turnaround to go from the worst team in the league to one of the final two teams competing for the Stanley Cup.

One lucky bettor placed a $400 wager on the Blues at 250-1 odds when things looked their worst, and now is just four wins away from cashing his ticket for $100,000.

For Las Vegas oddsmakers, it's the second straight year they've had to sweat the result of the Stanley Cup Final.

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For the second straight year, Las Vegas bookmakers are sweating the result of the Stanley Cup Final.

Last year, it was the upstart Golden Knights that brought potential liability to sportsbooks across the city, with local fans excited to support their hometown hockey team for their inaugural season. The Golden Knights came up just a few wins shy of lifting the trophy, with the Washington Capitals instead playing hero and saving casinos millions in potential losses.

Read more: Las Vegas sportsbooks save millions thanks to Capitals' Stanely Cup win over long-shot Golden Knights

This year, it's the St. Louis Blues who have oddsmakers nervous.

The Blues are currently fighting to win the Stanley Cup for the first time in franchise history. Facing off against the Boston Bruins, the team and its fans are entrenched in some of the tensest hockey they've ever played, having already survived two Game 7s to get to reach the Stanley Cup Final.

Through their postseason run, it's likely that no fan has sweat Blues' games more than Scott Berry, who could cash in for $100,000 if St. Louis lifts the Stanley Cup.

According to Darren Rovell at the Action Network, Berry placed his $400 bet on the Blues at the Paris Las Vegas Hotel back in January. At the time, the Blues looked lost, sitting among the dregs of the NHL standings as 250-1 long shots to win the Stanley Cup at Paris.

But Berry had faith, still wanting to back his team, and after realizing that the Blues odds to win the Cup were as low as 150-1 at other sportsbooks on the strip, made his move.

"So I sprinted back to the Paris and put down everything I had planned on spending on gambling — $400," Berry said. "To win $100,000 sounded really good."

Just days after Berry's bet was locked in, the Blues incredible run through the second half of the year began. Spurred on by the emergence of rookie goalie Jordan Binnington who would wind up sporting a .927 save percentage through the year, St. Louis climbed up the standings and back into playoff contention.

Since the Blues began their postseason run, Rovell says that Berry has turned down offers to sell his ticket for $12,000 and $24,000 — either of which would have represented a massive payout on his initial investment of $400 — but Berry has opted to let his bet ride.

Berry isn't the only person out there with such a story. According to ESPN's David Purdum, while there's not a ton of big bets on the Blues at such long odds, there are enough that the hit could cost the bookmakers big.

Bill Sattler, director of specialty games for Caesars Entertainment, said the Blues winning would cost the sportsbook a net loss of "mid-six figures," adding that it's a worse outcome than they would have had for the Golden Knights last year.

"You want people to bet the 250-to-1 longshots," Sattler told ESPN. "You just don't want those teams to go from last place to the Stanley Cup."

The Blues currently trail the Bruins 1-0 in the Stanley Cup Final, having lost Game 1 in Boston on Monday night. If St. Louis can turn the series around and lift the trophy for the first time in franchise history, Berry will be amongst the loudest fans cheering.

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