Then trainer Shug McGaughey's bay colt picked up speed, churning through a sloppy track that resembled creamy peanut butter, and blew past rivals one-by-one.
By that time, jockey Joel Rosario knew he was aboard the Kentucky Derby winner.
Orb powered to a 2 1/2-length victory Saturday at Churchill Downs, giving McGaughey and Rosario their first Derby wins.
"I was so far behind," Rosario said. "He was very relaxed, it's exactly what I wanted."
Rosario had Orb in the clear on the outside and they forged to the lead in deep stretch, with enough momentum to hold off 34-1 shot Golden Soul.
It was a popular victory before a crowd of 151,616, which poured enough late money on Orb to make him the 5-1 favourite, a position Revolutionary had owned most of the day.
McGaughey, a 62-year-old native of Lexington, finally got the Derby win he had long sought. Orb was just his second starter since 1989, when he settled for second after Sunday Silence beat Easy Goer on a muddy track.
"It means everything to me," the Hall of Famer said. 'I've always dreamed of this day and it finally came."
The rain that pelted the track earlier in the day had stopped by the time 19 horses paraded to the post for the 139th Derby. But it created a gloppy surface, although didn't seem to bother Orb who had never previously run on a wet track.
His triumph was a victory for the old school of racing, where a private trainer like McGaughey works exclusively for wealthy owners, in this case Stuart Janney and Ogden Mills "Dinny" Phipps.
The first cousins, among the sport's blue bloods that include the old-money Whitney and Vanderbilt families, also got their first gold Derby trophy.
Golden Soul, owned by Edmonton native Charles Fipke, was second. Revolutionary, one of trainer Todd Pletcher's five starters, was third. Normandy Invasion finished fourth.
Orb paid $12.80, $7.40 and $5.40. Golden Soul returned $38.60 and $19.40, while Revolutionary paid $5.40 to show.
Fipke was thrilled with his horse's second-place finish.
"It was unbelievable how he was coming on, with a little more distance, he might have won," the 66-year-old said. "I think he'll do really well in the Belmont Stakes, he's got the stamina to do it.
"It's nice to come second, but it's better to win."
Fipke had another horse in the field, with Java's War finishing 13th.
"I thought that Java's War would do better than it did," Fipke said. "I thought he would be able to handle the track, but he just didn't handle the soft track."
Meanwhile, history was denied on several fronts:
— Todd Pletcher's Derby record fell to 1 for 36 after sending out a record-tying five horses for the second time in his career. Besides Revolutionary, Charming Kitten was ninth; Overanalyze was 11th; early pacesetter Palace Malice was 12th; and previously unbeaten Verrazano was 14th.
— Rosie Napravnik's bid to become the first woman jockey to win ended with a fifth-place finish aboard Mylute. It was still the highest finish by a woman rider, bettering her ninth-place showing two years ago.
— Kevin Krigger failed in his attempt to be the first black jockey to win since 1902. He rode Goldencents to a 17th-place finish for trainer Doug O'Neill, who won last year with I'll Have Another. Rick Pitino owns five per cent of the colt, who couldn't deliver a horses/hoops double for the coach of the national champion Louisville basketball team.
— D. Wayne Lukas missed out on becoming the oldest trainer to win at 77. He saddled two horses: Oxbow was sixth with 50-year-old Gary Stevens making a Derby comeback after seven years in retirement, and Will Take Charge was eighth.
Being from Lexington, the heart of Kentucky's horse country, McGaughey figured to be a regular Derby participant. But Orb was just his second starter since 1989, when McGaughey watched Easy Goer lose to Sunday Silence.
Orb also was the second Derby starter for both Janney and Phipps, whose previous entries were in 1988 and '89. Their family wealth allows them to race the horses they breed, unlike the majority of current owners who are involved through partnerships that split up the exorbitant costs of the sport.
The cousins' grandfather, Henry Phipps, founded wealth management firm Bessemer Trust in 1907. Janney serves as chairman, while Dinny Phipps is its director. He also chairs The Jockey Club, the sport's governing body that registers thoroughbreds, while Janney is vice chairman.