CINCINNATI -- Pete Alonso felt going into the season that reaching 50 home runs was possible.
Now that he's there, it's become hard to believe.
"It was always in the realm of possibility," Alonso said. "It's hard to wrap my mind around it. It means the world to me, but I don't think I'll be able to appreciate it until after the season."
Cincinnati is 72-82, assuring itself a sixth straight losing season and 16th in 19 seasons.
Alonso is two homers shy of Yankees star Aaron Judge's 2017 total for the rookie record. The right-handed hitter connected on a two-run blast in the eighth inning against reliever Sal Romano, reaching for a down-and-away fastball and lining it an estimated 437 feet to the faux riverboat smokestacks in right-center field.
"The catcher reached down and to the right and he reached out and flicked it to the steam towers," New York manager Mickey Callaway said. "It was a well-executed pitch. I don't know what you do if you're a pitcher. (Former Red) Todd Frazier said he's never seen a left-hander hit one there."
Alonso is the second rookie to reach 50 homers, and he leads Cincinnati's Eugenio Suarez by two for most in the majors.
The Reds intentionally walked Alonso during New York's three-run ninth.
Cincinnati rookie Aristides Aquino led off the ninth with a homer. The midseason call-up has 17 home runs in 49 games this season.
DeGrom (10-8) struck out nine and didn't walk anybody to match his win total from last season, when he won the NL Cy Young Award. He could be a repeat winner after dropping his ERA to 2.51.
"I've been able to locate all my pitches and throw them when I want," deGrom said. "Having the feel of my curve and changeup and moving the fastball in and our helps keep them off balance.
McNeil broke up the scoreless tie with his 23rd homer, a towering drive into the visitors' bullpen down the right field line with one out in the sixth inning.
Rosario followed J.D. Davis's two-out walk with a two-run shot to left-center field, his 14th homer.
Those were two of the three hits allowed by Luis Castillo in seven innings. Castillo (15-7) struck out seven and walked three.
"We got to see first-hand why deGrom is so good," Reds manager David Bell said ."I saw really sharp stuff. He had it all going. I saw the same thing with Castillo. He was really good. You can't do much better than that. You'd like to have those two pitches back, but he was really good."
SEVENS ARE WILD
The start was deGrom's seventh straight and 11th in his last 12 in which he logged exactly seven innings.
Marty Brennaman, retiring this year after 46 seasons as a Reds broadcaster, and partner Jeff Brantley broadcast the game from a special booth built near a section of lower-level seats.
Reds pitcher Michael Lorenzen was honored before the game as the Reds nominee for the Roberto Clemente Award. Lorenzen, who also plays outfield, wears No. 21 in honor of Clemente.
Castillo's seven strikeouts boosted his season total to 218, good for a tie with Aaron Harag in 2007 for ninth on the franchise's single-season strikeout list. Tom Seaver is eighth with 226 in 1978.
Mets: RHP Robert Gsellman's bullpen session went "extremely well," Callaway said. A Saturday evaluation will determine whether the next step is pitching live batting practice. Gsellman has been out since August 14 with right triceps tightness.
Reds: Manager David Bell considers the return of OF Jesse Winker (cervical strain) this season "highly unlikely." Winker has been sidelined since August 22.
Mets: RHP Zack Wheeler (11-7) is 5-1 with a 2.93 ERA over his last 10 starts. New York is 7-3 in those games.
Reds: RHP Anthony DeSclafani (9-9) is 0-3 with a 6.75 ERA in four career starts against the Mets.
More AP MLB: https://apnews.com/MLB and https://twitter.com/AP-Sports
MLB playoffs 2021: Los Angeles Dodgers' Walker Buehler won't shy away from Game 6 pressure
Ahead of a crucial Game 6 showdown, L.A.'s young ace explains why nervousness helps, walks are better than hits, and the key to postseason success is a long drive and a good song.
Atlanta looks to clinch pennant with victory over Los Angeles
Los Angeles Dodgers (106-56, second in the NL West) vs. Atlanta Braves (88-73, first in the NL East)
MLB playoffs 2021 - Love them or hate them, the Houston Astros are really this good
No matter how much some despise Houston for its sign-stealing transgressions, there's no denying what this team is accomplishing now.
Alvarez: Astros showing we are the best team in the league
Yordan Alvarez discusses the Astros advancing to the World Series and how much they proved in beating the Red Sox.
2021 MLB playoffs: Schedules, postseason bracket, analysis and updates
All the latest information about the teams, storylines and highlights of the 2021 MLB postseason, from the start of October through the World Series.
Astros celebrate winning the ALCS
Players and coaches on the Astros celebrate after defeating the Red Sox to win the American League pennant and advance to the World Series.