The star jockey had been in action at Maisons-Laffitte in France only the day before, but showed no signs of fatigue as he partnered the four-year-old to her second Group 1 triumph after the Sun Chariot Stakes at Newmarket in late September.
Well placed on the rail, just off the pace, the favourite stormed through in the straight to ease home by a length and three-quarters from Pagera and Dream Peace.
“To be honest, I was not worried about the track, the ground or the filly,” said Mosse. “I was just a bit worried that two weeks ago we won a Group 1 in the UK so it was a bit short in timing. I had a good chat with the trainer before the start, though, and he convinced me. If he entered her, it was because she was competitive.”
Siyouma’s latest win earned her an invite to the Breeder’s Cup Filly and Mare Turf, though trainer François Doumen has turned it down, choosing instead to send her to Asia, where she will appear in the Queen Elizabeth II Commemorative Cup in Kyoto in November and the Hong Kong International Races in December.
Bred by the Aga Khan in Ireland and sold to Robert Jeffcock for nearly €295,000 in March 2012, Siyouma is finally justifying her hefty price tag.