Rosanara lived up to the hype to claim the Total Prix Marcel Boussac on Arc day at Longchamp. Touted by many shrewd judges as the new Zarkava, who won this race two years ago, the Alain de Royer-Dupre-trained filly showed plenty of class to preserve her unbeaten record.
Ridden by comeback kid Christophe Soumillon, whose return from injury this weekend has been nothing short of sensational, Rosanara comfortably justified favouritism - despite her relative inexperience.
It was not all plain-sailing for the Aga Khan-owned grey, who nearly unshipped Soumillon once the gates opened.
Her jockey also had to battle against the filly's rather head-strong tendencies inside the first couple of furlongs.
Once that issued was addressed, the Group One prize was there for the taking.
Rosanara had been smartly poised in fifth behind the front-running Kilo Alpha, but soon made smart progress entering the home straight.
A couple of smacks from her rider was all that was required as the 2-1 favourite slalomed down the centre of the track to handsomely defeat On Verra (33-1).
Joanna was third, while Aidan O'Brien's Cabaret was bitterly disappointing.
Rosanara has been installed as a 7-1 chance by William Hill for next year's 1000 Guineas and her rider was understandably delighted following her victory.
Soumillon, who is shortly to leave his retainer with the Aga Khan, said: "It's unbelievable - I'm in the sky right now and I don't want to come down."
Soumillon added: "She is a great filly, but different to Zarkava and you must not make comparisons."
The Aga Khan said: "We were very happy to have Christophe back. We were waiting to see how he got on yesterday, but he seemed to be fine.
"The filly tripped up when she broke from the stalls, but she is not a difficult ride and we were really happy with her."
In the first race of the day, Total Gallery sprung a surprise as he powered to victory in the Qatar Prix de l'Abbaye.
Trained by Stan Moore, the British raider made the leap to the highest level with a gutsy success under Johnny Murtagh.
Fleeting Spirit finished fast up the rail but could not peg back the winner, while War Artist just edged out Benbaun for third.