NEW ORLEANS—Midway through the second quarter of this Super Bowl, Chiefs quarterback Patrick Mahomes was desperate to conjure up some magic—any magic at all—just like he had so many times before.

His team was staring at zero points, just one first down and a two-score deficit. Making matters worse, Mahomes had just been sacked on back-to-back-plays. But unlike the countless occasions in his career when he has changed games with a single unbelievable play, this time he ran into a suffocating force.

It was called the Philadelphia Eagles.

Mahomes’s ugly third-down pass was intercepted by defensive back Cooper DeJean, who ran the ball back for a touchdown that put the Chiefs in a 17-point hole. And Kansas City, which had been chasing an unprecedented third consecutive Super Bowl, only kept sinking from there.

Football – NFL – Super Bowl LIX – Philadelphia Eagles v Kansas City Chiefs – Caesars Superdome, New Orleans, Louisiana, United States – February 9, 2025 Confetti is fired as Philadelphia Eagles celebrate after winning Super Bowl LIX REUTERS/Evelyn Hockstein

On a night that the Chiefs had hoped would turn into a supreme coronation, the Eagles delivered a Super Bowl beatdown for the ages, 40-22.

By the end of Sunday’s first half here, the Chiefs had run 20 plays to gain just 23 yards. Mahomes had completed just six of his 14 passing attempts. And the outcome was all but decided. Shortly after Mahomes’ first interception, he was picked off again near his end zone, setting up another quick Philadelphia score. At that point, there were still 30 minutes left to play but the result was no longer in doubt. The Eagles would be world champions once again.

“Defense wins championships,” said Eagles quarterback Jalen Hurts, who was named Super Bowl MVP. “We saw the difference they made. They gave us opportunities, gave us short fields and we were able to do what we do.”

The game was an even bigger blowout than the final score suggested. The Chiefs didn’t even get onto the scoreboard until late in the third quarter, when they were already down 34-0 with the game effectively over. It marked the first time all game that Kansas City had crossed midfield.

Fans celebrate after the Philadelphia Eagles win the Super Bowl LIX against the Kansas City Chiefs, in Philadelphia, Pennsylvania, U.S., February 9, 2025. REUTERS/Eduardo Munoz

The Chiefs may have been chasing history, but on Sunday night, the Eagles made their own claim as one of the defining teams in modern football. This was their second Super Bowl triumph in eight years and their third appearance during that run, having lost to Kansas City in this same game two seasons ago.

More than just sustaining success, the Eagles have also transformed the sport along the way. The last time they won the Super Bowl, they opened the football world’s eyes to the value of going for it on fourth downs. Then, over the past few years, their “tush push” quarterback sneak with Hurts has become one of the game’s most unstoppable, and most widely imitated, plays. Their knack for being on the cutting edge has often proven counterintuitive, too: at a time when so many other teams see little value in running backs, the Eagles used last offseason to make Saquon Barkley the highest-paid running back in the team’s history.

It all added up to a formula for Philadelphia to bring Kansas City’s dominance to a screeching halt.

Philadelphia’s first touchdown of the day came on a Hurts sneak and the team would have never reached this game without Barkley’s huge runs throughout the postseason.

But what swung the game was a retooled defense that completely shut down Mahomes. Their display was eerily reminiscent of the Buccaneers’ stifling performance in the Super Bowl four years ago, the only other time Mahomes has lost on this stage. On that night, when the Chiefs scored only nine points, Tampa Bay’s relentless pass rush and airtight secondary never gave Mahomes a chance.

This time around somehow turned out even worse. Mahomes was sacked six times, more than ever before in the playoffs. The vast majority of his 257 passing yards came when the game was out of hand. To add insult to injury, Mahomes gave the ball away again in the fourth quarter with a fumble, leading to a Philadelphia field goal that padded the score.

“Obviously, the turnovers hurt,” Mahomes said. “I take all the blame for that.”

The victory represents a remarkable turnaround for the Eagles, who were among the Super Bowl favorites last season until they crashed and burned down the stretch. Following a 10-1 start in 2023, they lost six of their final seven games, including a blowout playoff loss, raising questions about whether coach Nick Sirianni should keep his job.

While Sirianni was retained, general manager Howie Roseman oversaw a dramatic overhaul of the team. He hired new offensive and defensive coordinators. He brought in Barkley, who began his career with the rival New York Giants and became the engine of Philadelphia’s offense while putting up more than 2,000 rushing yards.

The new-look defensive unit, meanwhile, dominated a Chiefs offense that had been pedestrian for much of the season but burst to life once the playoffs started. DeJean, a rookie, made the first game-changing play. The next interception was made by linebacker Zack Baun, a bargain-bin free-agent signing who morphed into an All-Pro in his first season with Philadelphia.

It was such a decisive showing that by the time the teams went into the locker room for halftime, the only drama left in the stadium was whether rapper Kendrick Lamar would say anything about his nemesis Drake during his performance.

After a season that saw the Chiefs go on a remarkable run of pulling out close victories, the Eagles had left nothing to chance.

Write to Andrew Beaton at andrew.beaton@wsj.com and Joshua Robinson at Joshua.Robinson@wsj.com