2025 Eclipse Awards: Nitrogen

A promising maiden filly at the start of the season, Nitrogen rose to the head of her class in 2025 by building an exceptional multi-surface résumé worthy of Eclipse Award consideration as the nation’s outstanding 3-year-old filly.

It was trainer Mark Casse who came up with her name. Even before Nitrogen ran, Casse said he believed the filly “breathes different air.” Bred by her owner, D. J. Stable, the Medaglia d’Oro filly produced a different campaign in 2025. She won six stakes and excelled on every surface she raced over – turf listed firm and good, dirt listed sloppy and fast.

It turns out footing did not matter for Nitrogen, whose juvenile campaign in 2024 suggested she was a turf specialist. Her first three starts were on turf – runner-up in her debut against maidens, followed by a pair of third-place finishes in Grade 1 races, including the Breeders’ Cup Juvenile Fillies Turf at Del Mar. The best was yet to come in 2025.

Nitrogen launched her 3-year-old campaign in early January on turf at Gulfstream Park. She won the $150,000 Ginger Brew Stakes under Jose Ortiz, her jockey each of her last 10 starts. After a two-month break, Nitrogen resumed her campaign by winning the Grade 3 Florida Oaks in March at Tampa Bay Downs. She was just getting started.

:: Full list of 2025 Eclipse Awards finalists, including profile stories

After Grade 2 wins on turf at Keeneland and Churchill Downs, Nitrogen shipped to Saratoga for the Wonder Again Stakes, a Grade 2 scheduled to be run on turf. Due to rain, the race was moved to the Saratoga dirt track, listed sloppy. Nitrogen had never raced on dirt.

Casse and the D. J. Stable father-son team of Leonard and Jonathan Green considered scratching Nitrogen from the Wonder Again, which was downgraded to a Grade 3 due to the surface switch. Casse and the Greens rolled the dice and kept Nitrogen in the race. She defeated two rivals by 17 lengths for her fifth straight stakes.

Nitrogen returned to turf in the Grade 1 Belmont Oaks Invitational in July at Saratoga. She missed by a nose, then switched back to dirt for her final three starts. A good call by Casse and the Greens.

Nitrogen scored a decisive victory over Kentucky Oaks winner Good Cheer in the Grade 1 Alabama Stakes presented by Keeneland Sales at Saratoga, then met older fillies and mares for the first time in the Grade 1 Juddmonte Spinster Stakes in October at Keeneland in a prep for Longines Breeders’ Cup Distaff.

Nitrogen ran well in the Spinster, finishing second by a head to Gin Gin. It was on to Del Mar for the Breeders’ Cup Distaff. Nitrogen broke from the rail, raced in fourth position, launched a bid at pacesetting winner Scylla, and finished second. It was an outstanding run to cap an outstanding campaign.

Nitrogen won six races from nine starts in 2025, finished second three times, and earned $1,909,400. Her career totals: six wins from 12 starts and $2,046,604. Plans call for Nitrogen to campaign as a 4-year-old in 2026.

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