DENVER -- After securing a series win with back-to-back victories over the National League Central-leading Cardinals, the Rockies started six rookies in Thursday’s finale, losing 10-3 on the strength of four leadoff Redbirds roundtrippers in the first four innings.

The loss, combined with a Brewers win earlier in the day, left the Rockies mathematically eliminated from the postseason as they fell 23 games under .500 at 62-85.

• Box score

Most notable among Colorado's rookies’ highlights was a one-out solo homer from first baseman Josh Fuentes in the bottom of the second inning -- his first big league home run. Fuentes entered the game with two hits in 20 at-bats.

“I had some pretty good loft on it,” Fuentes said. “I hit first base, saw the trajectory on it and I thought, ‘Oh, man, it’s going out.’ Then all the emotions start flooding. You’re excited and just want to round those bases, get in the dugout and cheer with your teammates.

“It was probably one of the happiest moments in my life. Just above the first hit.”

Fuentes also entered the game with family on the opposite corner, as his cousin Nolan Arenado started at third and added his own one-out solo dinger in the third inning, offering fans a rare opportunity to see family members homering for the same team in the same game.

“I was like, ‘Man, you can’t even let me get the spotlight for 20 minutes?’” Fuentes said. “It was awesome for us to hit one on the same day. Hopefully more to come.”

Arenado was at least as proud as Fuentes, and not the least bit shy about stealing some of his cousin’s thunder.

“Dude, he had his fame for 20 minutes,” Arenado said. “It’s all right. It happens. I’ll buy him dinner tonight, he’ll be fine.”

Though tracking statistics for cousins in baseball can be a challenge, the last immediate family members -- brothers, or fathers and sons -- to homer for the same team in the same game were B.J. and Justin Upton, who accomplished the feat six times for the Braves, most recently on Sept. 27, 2014.

“It’s awesome,” Arenado said of the feat. “These moments are pretty cool. Obviously it’s tough when you lose, but we’re going to enjoy it. I know our families are. It’s a long road, and I know it hasn’t been easy for him. It hasn’t been easy for me. It’s always tough. So to be in the big leagues together and hit a home run in the same game is an amazing accomplishment.”

Before either of them homered, Arenado made one of the finest fielding plays of the season, chasing a foul pop into the sun down the third-base line, catching it over his shoulder, and -- in a single motion -- spinning and throwing a Hail Mary to the plate, where rookie Dom Nuñez caught it on a short hop but dropped the ball in a home-plate collision with Harrison Bader, who had tagged up at third base.

“I thought we had him, I was fired up, but it turned from fired up to disappointed,” Arenado said. “It was a tough play for Dom. I could have planted my feet a little better.”

Starting pitcher Tim Melville -- a rookie who had six big league games (three starts) under his belt before returning to the Majors with Colorado on August 21 -- had a rough day on the mound. He entered the game with a 3.66 ERA and a 2-1 record, but his ERA ballooned to 5.16 after giving up five runs on five hits in three innings.

Rockies Opening Day closer Wade Davis struggled mightily in the ninth, entering with Colorado down by three and loading the bases with two walks and a hit batsman before yielding a two-run double to Matt Carpenter and exiting the game before recording an out.