NEW YORK -- Mets first baseman Pete Alonso, the odds-on favorite to win National League Rookie of the Year, reached another milestone Tuesday night, setting the single-season franchise record by hitting his 42nd home run.

Alonso, 24, took an outside fastball from Chicago Cubs starter Yu Darvish deep to right field to lead off the fourth inning. According to Elias Sports Bureau, Alonso is the first rookie to set the franchise mark for his team since Johnny Rizzo did it for the Pittsburgh Pirates in 1938.

"As soon as that ball came off my bat, I knew right away," Alonso said after the game. "I mean it's become a dream come true so far this year and I just feel really blessed."

Alonso received a curtain call for his record-setting blast, which gave the Mets a 1-0 lead.

The previous franchise mark of 41 home runs was set by Todd Hundley in 1996 and matched by Carlos Beltran in 2006.

"It's a pleasure to have a fine young player like Pete Alonso break my record," Beltran said in a statement. "I have not met Pete personally, but people have told me he plays the game with passion and doesn't give up on any at-bat. He has had great success in his first year. Again, my congrats, Pete."

Hundley also praised Alonso.

"To me, he's more than a power hitter, he's a pure hitter," Hundley said in a statement. "I have seen five or six of his games and he keeps getting better and better. He has just had a tremendous year. Congrats, Pete, you deserve all the records you have broken."

Alonso's homer was his lone hit in four at-bats, and the Cubs rallied to win 5-2.

Earlier this month, Alonso set the National League rookie record for homers in a season, previously set by Cody Bellinger of the Los Angeles Dodgers in 2017. Aaron Judge of the New York Yankees holds the major league record for home runs in a season by a rookie with 52 in 2017.

"It's crazy to think the small selection of people that get to actually play in the big leagues and the even smaller selection of people that get to those milestones and it's mind-boggling," Alonso said. "I just wanna keep being Pete Alonso and just stay true to who I am and stay true to who I am not just as a person but as a player."