There were tears and also an expression of wide-eyed disbelief on Spencer's impossibly youthful features as he was led back to dismount, but then he had only been confirmed as Tarascon's partner - his first ride in a Classic - less than 72 hours beforehand. He grasped the chance with both hands, wisely holding his mount up as Shahtoush made the running, and then delivering an irresistible challenge down the stands rail to beat Kitza and La Nuit Rose, the favourite.
Spencer was a late replacement for Pat Smullen, who rode Tarascon in the 1,000 Guineas at Newmarket, when she became agitated entering the stalls and ran dismally once she had left them, finishing last of 16 to Cape Verdi. The start was again a problem for her, and it required all the stubborn determination that four handlers could muster before Tarascon could be locked away, but once the field was on its way, her problems were quickly forgotten.
"Tommy told me on Friday that I would be riding here and I've been thinking about it ever since," Spencer said. "She had the run of the race, and two furlongs out I thought we might be placed, and then after that I thought she would win."
Stack, who rode Red Rum to his third victory in the Grand National four years before Spencer was born, had tried - no doubt forlornly - to play down the significance of the race for his young jockey. "I said to Jamie that it is just an ordinary race and if she runs bad, there is no panic, there isn't any pressure," he said. "He has got a bright future. He has been riding work for the last month and I was pleased with the way she went for him, and he did very well."
In theory, there are now plenty of options for Tarascon, but an unfortunate incident on the way to Newmarket three weeks ago may in practice leave Stack with little choice. The filly cut a leg after being frightened by a 747 at Stanstead airport, and her trainer is reluctant to risk a repeat. So while she holds entries in both the Oaks and Prix de Diane (French Oaks), the Irish equivalent is an attractive alternative.
The first Classic weekend of the Irish season did not proceed according to plan for Aidan O'Brien, who saddled Kitza to finish second yesterday but saw both Shahtoush, the runner-up to Cape Verdi at Newmarket, run poorly after taking a long walk in the market. Just as strange was the performance of Second Empire in the Irish 2,000 Guineas on Saturday, when the previously unbeaten colt - and hot favourite - appeared to finish full of running in third place with Christy Roche, his jockey, reluctant to even shake his reins.
The Curragh stewards noted - rather than accepted - Roche's version of events, but O'Brien was quick to defend his jockey. "Everybody is human, and things happen," he said. "That was just the way it happened on the day. Christy said that it was a mess of a race, that the pace was on up front, and the horse was out the back and got caught in a separate race. When the first two kicked, the race was over. Christy thought there was no point in giving the horse a hard race to go and follow them. He accepted he was going to be third."
Roche, meanwhile, said that he had ridden Second Empire "like I ride all the good horses".
"He was near enough if good enough. I wasn't thinking of the Derby for Second Empire, I was thinking of yesterday's 2,000 Guineas. But he lost ground rather than gained ground on the winner in the last two furlongs."
Second Empire remains 7-4 favourite "with a run" for the Derby with William Hill, but the make-up of O'Brien's Epsom challenge remains undecided. "I would say to anyone who is thinking of backing any of them, back them with a run," the trainer said, "because at this stage we are in a fortunate position that we have some very smart colts."
What punters who were on Second Empire on Saturday may point out, however, is that even though their horse turned up, they did not get a run for their money.
IRISH 1,000 GUINEAS
1. TARASCON (J P Spencer) 12-1; 2. Kitza 16-1; 3. La Nuit Rose 9-4 fav. 13 ran. neck, 2. (T Stack). Tote: pounds 16.70; pounds 4.10, pounds 6.80, pounds 1.90. RF: pounds 157.50. CSF: pounds 179.95.
Also ran: 4. Winona; 5. Crazee Mental; 6.= Mempari & Silca Key Service; 8. Cloud Castle; 9. Heed My Warning; 10. Shahtoush; 11. Attractive Crown; 12. Time Limit; 13. Sharp Catch. After stewards' inquiry, result unaltered.
OAKS (Ladbrokes): 6-4 Bahr, 2-1 Midnight Line, 7-1 High And Low, 10-1 Tarascon (from 33-1), 12-1 Cloud Castle, 20-1 others