Hall of Fame trainer D. Wayne Lukas has never been afraid of running top-class fillies and mares against males, and through the years that strategy has paid off with some memorable victories.

A brief glance through the list of Lukas’ top female runners reveals names such as Winning Colors (triumphant in the 1988 Kentucky Derby), Serena’s Song (winner of the 1995 Haskell Invitational), Althea (victorious in both the 1983 Del Mar Futurity and 1984 Arkansas Derby), and Surfside (winner of the 2000 Clark Handicap). But perhaps none of those terrific racemares is quite as renowned to this day as the great Lady’s Secret, whose memorable victory in the Grade 1 Whitney Handicap in 1986 was a major milestone during a Horse of the Year season.

Physically, Hall of Famer Lady’s Secret was not the type of filly that horsemen typically consider a good fit for racing against males. It’s common to hear that big, strong fillies are considered better-suited to contesting tough races against males — for example, Zenyatta and Rachel Alexandra both fit that profile in recent years.

In contrast, Lady’s Secret was about as small as racehorses come; according to the Eclipse Press book “Horse Racing Divas: From Azeri to Zenyatta, Twelve Fillies and Mares Who Achieved Racing’s Highest Honor,” Lady’s Secret stood just an inch over five feet tall at her withers and weighed just 950 pounds. But what she lacked in size, she made up for with speed, soundness, durability, and heart.

“She was the ultimate overachiever,” said Lukas in the book “Thoroughbred Champions: Top 100 Racehorses of the 20th Century,” published by the BloodHorse. “Early in her career, we didn’t think she had superstar potential. In fact, we weren’t even sure she would achieve stakes-winner status. … But she was very, very tough, and hickory sound.”

That durability — coupled with her striking gray color — earned her the nickname “the Iron Lady.” It was a fitting title, for by the time she arrived at Saratoga for the Whitney, she was already of veteran of 33 starts. With 10 graded stakes wins under her belt, she had repeatedly conquered her fellow fillies and mares with authority, and she had also held her own against males in the prestigious Grade 1 Metropolitan Handicap at Belmont Park, finishing a close third after leading into the homestretch.

Even prior to the Whitney, her 1986 season had been impressive enough to hint that a Horse of the Year title could be within reach if she could defeat males at the Grade 1 level. And where better to give the task a try than at Saratoga, where Lady’s Secret had gone 2-for-2 the previous summer?

Thus, Lady’s Secret’s name turned up in the entries for the 1 1/8-mile race, alongside that of her Lukas-trained stablemate Fuzzy. The pair was coupled in the wagering and favored to win, with the 1985 Haskell Invitational winner Skip Trial and the versatile veteran Ends Well among the other main contenders.

But ultimately, the names of her rivals became mere footnotes in the history books. In the scheme of the race, they were hardly consequential, because Lady’s Secret never gave them even the slightest chance at victory.

From start to finish, her performance was a tour de force. For a few strides after the gates opened, longshot Sunny Galore tried to make a race of it, but Lady’s Secret — under hard urging from jockey Pat Day — quickly seized command heading into the first turn, briefly drifting wide as if to discourage Sunny Galore before dropping back to the rail, and sprinting three lengths clear of a strung-out field.

At that point, the race was all but over. Lady’s Secret, happily splashing along the sloppy track, rattled off steady fractions of :23 1/5, :46 3/5, and 1:10 4/5 while giving the impression of being out for a morning stroll. Her competition never got close; it was as if they recognized her superiority and conceded her the victory, settling into a battle for second place while paying respect to the front-running “Iron Lady” cruising out ahead of them.

Oh, one or two of them made a token attempt to give the race some semblance of excitement. On the far turn, Ends Well moved up along the inside and drew within about 1 ½ lengths of the lead, but Lady’s Secret had yet to be asked for her best. When Day urged her lightly at the top of the stretch, Lady’s Secret turned back Ends Well with ease and powered away to win by 4 ½ lengths, stopping the clock in 1:49 4/5 while becoming the first female to win the Whitney since Gallorette in 1948.

Her impressive performance was cheered by a large crowd of more than 43,000 people, and it did not go unnoticed by Eclipse Award voters. By the end of the year, Lady’s Secret had run two more solid races against males and capped the year with four straight Grade 1 wins against fillies and mares, culminating with an easy score in the Breeders’ Cup Distaff. Her record for the season stood at 10 wins from 15 starts, including eight Grade 1 victories, a streak of success that made her a clear choice for Horse of the Year.

Would she have earned the title without her effortless triumph in the Whitney? We’ll never know for sure. But there can be no doubt that the sight of Lady’s Secret cruising down the Saratoga homestretch, dominating a quality field of male rivals chasing her in vain, played a significant role in stamping her as one of the greatest fillies or mares ever seen on the American turf.