Madison Square Garden, the mecca of boxing, has hosted countless legendary fights since the 1920s. While the venue is famous for epic battles and coronation nights for champions, true massive upsets—where overwhelming favorites were shockingly defeated—are relatively rare. When they do happen at The Garden, they become instant history.
Here are the five biggest upsets ever at MSG, ranked by shock value, betting odds, pre-fight expectations, and long-term impact.
1. Andy Ruiz Jr. TKO7 Anthony Joshua
June 1, 2019
The most stunning heavyweight upset of the modern era—and one of the biggest in boxing history—happened right here in Joshua’s American debut. The unified champion was a colossal favorite (odds as high as -3000), expected to steamroll late-replacement Ruiz. Instead, the chubby underdog from California dropped Joshua four times and stopped him in seven rounds to become the first Mexican heavyweight world champion. The shockwaves rivaled Buster Douglas over Mike Tyson.
2. Vilomar Fernandez SD10 Alexis Arguello
July 26, 1978
One of the most overlooked monster upsets in boxing lore. Arguello, the undefeated Nicaraguan superstar and newly crowned WBC super featherweight champion, was a 10-1 favorite (some reports say even higher) against journeyman Fernandez. In a massive stunner, Fernandez took a split decision and the title, handing “El Flaco Explosivo” the first loss of his Hall of Fame career.
3. Srisaket Sor Rungvisai MD12 Roman “Chocolatito” Gonzalez
March 18, 2017
Gonzalez entered as the consensus pound-for-pound king and an -800 favorite, riding a decade-long unbeaten streak. Thai warrior Rungvisai, a heavy underdog, knocked him down in the first round and outfought him over 12 brutal rounds to win a majority decision. The loss ended Chocolatito’s reign atop the sport and remains one of the most jarring P4P shocks of the 21st century.
4. Vernon Forrest UD12 Shane Mosley
January 26, 2002 (The Theater at Madison Square Garden)
“Sugar” Shane Mosley was the welterweight king, a pound-for-pound elite, and a -400 to -500 favorite. Tall, rangy underdog Vernon Forrest dropped him twice and thoroughly dominated him en route to a clear unanimous decision. The victory announced Forrest as the new man in the division and marked one of the welterweight era’s biggest passing-of-the-torch moments.
5. Joe Frazier UD15 Muhammad Ali
March 8, 1971 – “The Fight of the Century”
Both men were undefeated, but Ali—returning from his three-year exile—was the betting favorite (roughly -170 to -200). Smokin’ Joe had other plans. Frazier floored Ali with the famous left hook in the 15th round and won a convincing unanimous decision, handing “The Greatest” his first professional defeat in front of a celebrity-packed Garden crowd on one of the most iconic nights in sports history.
These five fights stand above the rest for the sheer magnitude of expectation they overturned. Madison Square Garden has seen plenty of close, competitive classics, but when a true underdog shocks the world under those bright lights, it becomes legendary.
