His Highness The Aga Khan, Christophe Soumillon, Alain de Royer Dupre (Stephane De Sakutin/AFP/Getty) The Aga Khan’s homebred filly Zarkava (Ire) ( Zamindar ) had Longchamp holding its breath when making it a magnificent seven career wins and a fifth at the highest level in yesterday’s G1 Prix de l’Arc de