Lieutenant's Lark, a 37-1 shot, led from start to finish to win the $600,000 Washington, D.C. International by a neck at Laurel, Md.
The Kentucky-bred colt covered the soggy 1-mile turf course in 2:09 to earn a purse of $360,000.
Lieutenant's Lark, who finished ninth in the Breeders' Cup Mile at Santa Anita, edged hard-charging Dance of Life. Palace Music was third by one length.
"We tried to see how slow we could go and still outfinish them," winning rider Robbie Davis said. "He was going so easy in the first turn and the backstretch, I couldn't believe nobody came up to challenge me."
Lieutenant's Lark paid $76.60, $14.40 and $9.40; Dance of Life returned $4.80 and $3.40, and Palace Music paid $3.40.
Broad Brush, the hometown favorite who finished third in the Kentucky Derby and Preakness Stakes, was scratched when the course, described as "soft," did not dry out.