Alonso becomes just the third back-to-back Home Run Derby champion in MLB history, joining Hall of Famer Ken Griffey Jr. (1998-99) and former Mets star Yoenis Cespedes (2013-14). Alonso's two Derby crowns occurred over three seasons after the 2020 event was canceled due to the COVID-19 pandemic.
Needing six home runs in one minute to win the final, the 26-year-old Alonso hit six bombs on six swings over a 28-second stretch to eclipse the 22 long balls hit by Mancini during his final round.
"I'm the best power hitter on the planet," Alonso proclaimed after the win. "Being able to showcase that and put on a fun display for the fans is truly a dream come true for me."
Alonso began his title defense by bashing a first-round record 35 homers to eliminate the Kansas City Royals' Salvador Perez. In the second round, Alonso knocked off the Washington Nationals' Juan Soto, who defeated Los Angeles Angels star Shohei Ohtani in the opening round after two tiebreakers.
Mancini, who was the No. 6 seed and a long shot to win the Derby, defeated third-seeded Matt Olson of the Oakland Athletics in the first round, then beat the Colorado Rockies' Trevor Story in Round 2 to reach the final. Story edged Texas Rangers slugger Joey Gallo in the opening round.
The 29-year-old Mancini made his return this season after previously undergoing treatment for colon cancer. He was diagnosed during spring training last year and missed the pandemic-shortened 2020 campaign.
"He's a good dude," Olson said. "To be able to battle the way he battled and come back and perform the way he has this year says a lot about him, his grit and his toughness."
Soto thrilled the sold-out crowd of 49,048 in Denver with a 520-foot home run, which was the longest Derby blast in the Statcast era. The drive topped the 513-foot homer from New York Yankees star Aaron Judge in 2017 at Miami.
The Mets first baseman earned $1 million -- more than his $676,775 salary -- for the victory. He has now racked up $2 million in Derby winnings over the past three seasons compared to about $1.47 million in career salary over that same span.