Despite their status as defending champions, the Kansas City Chiefs are slight underdogs when they face the San Francisco 49ers in the 2024 Super Bowl in Las Vegas today.

The Niners first opened as 1.5-point favorites, according to most sportsbooks. The line has since shifted even more in their favor, with San Francisco settling in as consensus 2-point favorites by Saturday afternoon. 

Oddsmakers have the consensus over/under at 47.5 points. However, according to Pro Football Reference, the Chiefs had the No. 2 ranked defense in the NFL this season, with the Niners right behind them at No. 3, so a low-scoring affair could be in order.

Patrick Mahomes comfortable as the underdog

Playing as an underdog appears to suit Chiefs star quarterback Patrick Mahomes just fine. This last month saw the Chiefs face arguably their toughest challenge yet in the Mahomes era, as the two-time MVP remarkably found himself playing road playoff games for the first time ever in his NFL career.

As road underdogs, the Chiefs first edged the Buffalo Bills in frigid conditions in the divisional round, and then again when they bested the Baltimore Ravens in the AFC title game, with Mahomes throwing two touchdowns to tight end Travis Kelce.

In his career, Mahomes has a stellar 10-1-1 record against the spread as an underdog, according to ESPN.

San Francisco 49ers look to silence doubters

The Niners, however, arrive at Super Bowl LVIII on much shakier ground. Despite earning a No. 1 seed and home field advantage, they struggled mightily against seemingly inferior NFC competition.

They entered their divisional matchup with the seven-seeded Green Bay Packers as 10.5-point favorites. But the Packers took a 21-14 lead into the fourth quarter, and looked poised to pull the upset, before the Niners rattled off 10 unanswered points to clinch a 24-21 comeback win thanks to a Christian McCaffrey touchdown with just over a minute to go.

The narrative going into the NFC title game followed a similar script, with the Niners as 7.5-point favorites over the Detroit Lions. But the Lions dominated early, taking a 24-7 lead into halftime before they collapsed and the Niners rallied with 28 unanswered points to earn a 34-31 win.

If Mahomes embodies experience, San Francisco represents uncertainty. When the Chiefs defeated the Niners 31-20 in Super Bowl LIV four years ago, the Niners were led by quarterback Jimmy Garoppolo. He is gone, replaced by Brock Purdy — "Mr. Irrelevant," the last pick of the 2022 draft. Purdy has had an up-and-down playoffs, throwing just two touchdowns against one interception.

Niners head coach Kyle Shanahan may have the most to prove Sunday. Since taking the reins in San Francisco, he is 0-3 against Chiefs head coach Andy Reid, with the latest loss coming in a 44-23 drubbing by the Chiefs in 2022.

Reid and the Chiefs are seeking their third Super Bowl in just five years and their fourth as a franchise. San Francisco is looking to win its first Super Bowl since 1995 and its sixth overall. 

How accurate have Super Bowl predictions been in the past?

In Vegas, the moniker is the house always wins, and that also applies to the Super Bowl. According to the betting data site Covers, since 1991, Nevada sportsbooks have only lost money on the Super Bowl twice in its history.. The first instance occurred in 1995, when the Niners crushed the then-San Diego Chargers 49-26. The second famously occurred in 2008, when Eli Manning's New York Giants upset Tom Brady's heavily-favored New England Patriots, thwarting their efforts to complete a perfect 19-0 season.

Every year, EA Sports runs a simulation of the Super Bowl on its popular Madden video game. In last year's simulation, the Philadelphia Eagles defeated the Chiefs 31-17, but that was far off the actual result, in which the Chiefs won a 38-35 nailbiter.

According to Sports Illustrated, since 2004, the EA Sports Madden Super Bowl simulation has accurately predicted the winner 55% of the time. In Super Bowl XLIX in 2015, the simulation was perfect, not only predicting that the Patriots would defeat the Seattle Seahawks, but also getting the score exactly right, 28-24.

In the EA Sports Madden simulation for Sunday's game, the Chiefs defeated the Niners 30-28.

Super Bowl LVIII will air on CBS and Nickelodeon and stream on Paramount+ on Feb. 11 from Allegiant Stadium in Las Vegas. Kickoff is scheduled for 6:30 p.m. ET. Preshow and halftime performers include Usher, Reba McEntire and Andra Day.

In:
• Kansas City Chiefs
• San Francisco 49ers
• Super Bowl LVIII
• Super Bowl

Faris Tanyos

Faris Tanyos is a news editor for CBSNews.com, where he writes and edits stories and tracks breaking news. He previously worked as a digital news producer at several local news stations up and down the West Coast.