Young British eventer Laura Collett laid down an early-season marker by taking a convincing overnight lead in the Belton Horse Trials' feature class.
Wiltshire-based Collett and Rayef, top-10 finishers on their Badminton debut last year, delivered an impressive dressage test to take charge of the Grantham Cup CIC three-star competition.
Collett, 22, is among the contenders for a place in Great Britain's five-strong Olympic team for London this summer, and she rose to the challenge to head a 103-strong field.
Collett and Rayef led last year's Badminton after day one of dressage, and the experienced combination posted a score of 39 penalties moving into Sunday's showjumping and cross-country sections.
The combination competed as individual British hopes at last summer's European Championships in Germany before bowing out during a punishing cross-country phase.
And they again underlined rich potential to lead by 2.4 penalties from five-time Olympian Mary King (Imperial Cavalier), with Kent's Emily Baldwin (Drivetime) third, Willa Newton (Neelix) fourth and last year's Grantham Cup winner Oliver Townend (Arctic Mouse) fifth.
Slightly further down the leaderboard there was another solid comeback performance by Tina Cook and a fit-again Miners Frolic, team and individual Olympic bronze medallists four years ago, in ninth spot.
And earlier in the day, there were intermediate section wins for reigning Badminton champion Mark Todd and Australian Bill Levett.