A champion at 2 and 3, Nitrogen’s quest to become a champion at 4 begins Saturday at Oaklawn in the $250,000 Bayakoa Stakes (G3) for older fillies and mares.

The Bayakoa headlines an 11-race card that begins at noon (Central). The 1 1/16-mile Bayakoa goes as the ninth race, with probable post time 4:13 p.m.

Nitrogen, a homebred for D J Stable (Jon and Leonard Green) and dual Hall of Fame trainer Mark Casse, won a Sovereign Award as Canada’s champion 2-year-old filly in 2024 and an Eclipse Award as North America’s champion 3-year-old filly of 2025.

During a busy nine-race campaign last year, the versatile Nitrogen captured six stakes, including the Alabama (G1) at 1 ¼ miles Aug. 16 at Saratoga, off-the-turf Wonder Again (G3) at one mile June 7 at Saratoga, grassy Edgewood (G2) at 1 1/16 miles in May at Churchill Downs and the grassy Appalachian (G2) at one mile in April at Keeneland. Nitrogen hasn’t started since finishing second against older females in the Breeders’ Cup Distaff (G1) at 1 1/8 miles Nov. 1 at Del Mar.

Casse is using the Bayakoa as Nitrogen’s bridge to Oaklawn’s $400,000 Azeri Stakes (G2) on March 7 and the $1.25 million Apple Blossom Handicap (G1) April 11.

“I had kind of thought that I wouldn’t run her until the Azeri, but she’s sharp,” Casse said. “One, I brought her back a little quicker than I planned just because she doesn’t handle time off well. She’s got a lot of energy and I was afraid she was going to hurt herself resting, so I put her back in training a little quicker than I anticipated. Still, at that point and time, I thought that we would probably still be going to the Azeri. But she started training so well that the Bayakoa then ended up on our radar.”

Casse said Nitrogen resumed training in late November. Nitrogen had two published workouts (Dec. 31 and Jan. 7) at Casse’s Florida training center before shipping to Oaklawn. She arrived Jan. 11. Nitrogen posted a five-furlong bullet workout (1:00) Jan. 17. The track was then closed for training for nine days (Jan. 24-Feb. 1) because of a winter storm.

“Her last work at Oaklawn was really good – galloped out strong,” Casse said. “It would have been nice to have one more breeze, but she’s ready.”

Nitrogen, the 4-5 program favorite, drew post 7 in the seven-horse field. Regular rider Jose Ortiz has the mount. Nitrogen is by Medaglia d’Oro, who broke his maiden at the 2002 Oaklawn meeting for trainer David Vance and returned to win the 2003 Oaklawn Handicap (G2) for Hall of Fame trainer Bobby Frankel. Nitrogen, overall, has a 6-4-2 record from 12 starts and earnings of $2,046,604.

Nitrogen’s biggest challenger on paper is multiple Oaklawn stakes winner Quietside, a homebred for John Ed Anthony’s Shortleaf Stable and trainer John Ortiz.

Quietside, under Jose Ortiz, won two 1 1/16-mile races last year at Oaklawn – $500,000 Honeybee Stakes (G3) and $750,000 Fantasy Stakes (G2). Quietside (3-1) exits a second in the Comely Stakes (G3) at 1 1/8 miles Dec. 7 at Aqueduct.

Nerazurri, Rose Palace, Peignoir, Miss Authentic and In Just My Heels complete the field.

Nerazurri (7-2) is two-for-two this season at Oaklawn, including a front-running 3 ½-length score in the inaugural $135,000 Oaklawn Sports Overnight Stakes at 1 1/16 miles Jan. 1.

“That race (Bayakoa) has always been a target for Nerazurri,” Casse said. “The one that was kind of new was Nitrogen.”