Pete Alonso has entered the Major League Baseball history books…

The 28-year-old half-Spanish American professional baseball player, nicknamed “Polar Bear,” homered twice and drove in four runs, reaching 40 homers and 100 RBIs for the second consecutive season as the New York Mets beat the first-place Seattle Mariners 6-3.

Alonso, a three-time MLB All-Star, hit an RBI single in the first inning before his two-run shot in the third made him the fifth player in major league history with at least three 40-homer seasons in his first five campaigns, joining MLB Hall of Famers Ralph Kiner (four times), Eddie Mathews, Ryan Howard and Albert Pujols.

“Kind of mind-baffling,” Alonso said. “Impressive names. I had no idea.”

Jeff McNeil also went deep — after finishing a homer shy of the cycle Saturday night — and New York took two of three games from the Mariners to hand them their first series loss since Aug. 11-13 against the Baltimore Orioles.

“It’s been a while,” Seattle manager Scott Servais said.

Seattle, which won a franchise-record 21 games in August, began the day leading the American League West by one game over the Houston Astros.

“We just had a historic month for the organization, and we had maybe a little setback here,” said M’s first baseman Mike Ford, who hit the second of back-to-back homers in the fourth. “But we can get right back on it.”

Alonso’s solo homer in the seventh made him the fourth player in Mets history with at least three 100-RBI seasons. David Wright reached the 100-RBI milestone five times, and Carlos Beltrán and Darryl Strawberry each did it three times.

“Through thick and thin, we know one thing: Pete’s going to walk through that door the same guy every day,” Mets manager Buck Showalter said. “Pleasure to be around. He never has a bad day. He cares about his teammates, cares about the Mets. And to see guys like him have success, it makes it even more enjoyable.”

Alonso’s 41 home runs are tied for the second most in a season in franchise history with Beltrán and Todd Hundley. Alonso holds the team record with 53 as a rookie in 2019.

“It seems like yesterday I was in my rookie season,” Alonso said. “This is my fifth year, and time flies. It means a lot. This place has been extremely special to me. New York’s treated me so incredibly well.”

Alonso can become a free agent following the 2024 season, and speculation has been heating up about whether the retooling Mets will trade him this winter after dealing away veteran aces Max Scherzer and Justin Verlander over the summer to restock the farm system.

“Everybody knows that’s part of the game until the contract is done,” New York shortstop Francisco Lindor said.