American Pharoah’s final race, the Breeders’ Cup Classic, was supposed to be the test that measures how great a horse he may be. He has already earned a place in history by sweeping the Triple Crown, dominating a 3-year-old crop of average quality. But 3-year-olds don’t fully prove themselves until they face older rivals, and plenty of formidable ones were entered to challenge American Pharoah on Saturday at Keeneland – the champion mare Beholder; the powerful stretch-runners Honor Code and Tonalist; the brilliant, tenacious speedster Liam’s Map. Beholder, expected to be second choice in the wagering, was withdrawn from the race Thursday when blood was found in her trachea after her morning exercise. Earlier, the management of Liam’s Map made the decision to duck the $5 million Classic and run instead in the $1 million Dirt Mile on Friday. As a result, the complexion of the Classic has been changed significantly. The field of nine is left with a solitary front-runner. American Pharoah has scored half of his victories by leading all the way, while none of his rivals has taken the early lead in any race. American Pharoah has been a lucky horse all season, and the configuration of the Classic gives him a formidable tactical advantage. These developments disappoint me as a fan, because I wanted to see American Pharoah demonstrate whether he deserves to be considered an all-time great. As a gambler, I was disappointed, too, because I wanted to bet against him. Despite all of the accolades he has received, he has regularly been the beneficiary of easy trips and has earned unexceptional speed figures. I believe he would not have won Saturday with Liam’s Map in the field.  The lack of speed in the Classic will hamper the late-running Honor Code, Tonalist, and Keen Ice, who upset American Pharoah in the Travers Stakes after a contentious pace took a toll on the favorite. Smooth Roller is one of the few challengers who can sit within striking of American Pharoah. If the favorite falters, Smooth Roller might have the chance to pull off an upset, but that is a longshot proposition at best. With the Triple Crown winner likely to be cruising on an uncontested early lead, it is hard to muster a strong anti-Pharoah conviction. The second-richest race of the Breeders’ Cup, the $3 million Turf, may not be too competitive either. That’s because Golden Horn is too good. He has already won Europe’s two most important races, the Epsom Derby and the Prix de l’Arc de Triomphe. If he wins the Turf, his sweep of these events will be an historic feat, comparable in magnitude to what American Pharoah is trying to do. But while the competition is not deep in the main events, most of the other Breeders’ Cup races Saturday are challenging (and sometimes inscrutable) handicapping puzzles. These are my main plays:  Turf Sprint (race 4): The event is a wide-open 14-horse scramble, as always, but Pure Sensation possesses unassailable credentials. His lifetime record in grass sprints is 3 for 3. He dueled through a torrid 44-flat half-mile in his last start and still finished well to win. He is trained by a turf master, Christophe Clement. He drew the favorable post 1. And his morning-line odds of 6-1 represent excellent value.  My exacta horses: Mongolian Saturday and Lady Shipman. Filly and Mare Turf (race 6): Europeans usually dominate the grass races in the Breeders Cup, and Legatissimo is considered the best of the invaders; she’s a heavy favorite in British betting pools. But trainer Chad Brown beat the Europeans in this event last year, and he can do it again with Dacita. An import from Chile, the filly came off an eight-month layoff to win her U.S. debut at Saratoga. She did so by running the final quarter-mile in a sensational 22.32 seconds, and won a photo finish over Tepin, who subsequently captured a Grade 1 stakes race by seven lengths. With her late kick, Dacita can beat the Europeans at their own game. Sprint (race 7): Runhappy is a freakish talent, possessing extraordinary raw speed. He is faster than all of the other fast horses in the Sprint. If he breaks cleanly (which he does not always do), he’ll outrun his rivals and discourage the habitual front-runners among them. I’ll play exactas with Runhappy on top of two stretch-runners, Stallwalkin’ Dude and Salutos Amigos. Juvenile (race 9): Unbridled Outlaw may not be good enough to win this race for 2-year-olds, but he’s much better than he looks on paper after having encountered serious trouble in his prior starts. He’s been squeezed; he’s been checked; he’s hit the rail. He’s due for a little luck. Three contenders in the Juvenile have more obvious virtues – Greenpointcrusader, Brody’s Cause, and Exaggerator – but they are hard to assess because they ran their best races over muddy tracks. My plan is to play a four-horse trifecta box of Greenpointcrusader (No. 3), Unbridled Outlaw (4), Brody’s Cause (7), and Exaggerator (9) and hope that Unbridled Outlaw gets onto the ticket at a big price. © 2015 The Washington Post