Sun Cap's dam Cappellina, from whom she inherited her grey colour, won only two minor races from thirty-two starts but did better as a broodmare, producing the Prix Jean Prat winner La Varende, as well as Bebob, the female-line ancestor of Stop The Music and Spend A Buck's sire Buckaroo.
[2] Sun Cap began her second season by winning the Prix Penelope over 2100 metres at Saint-Cloud Racecourse on 18 April at odds of 30/1.
[5] The 176th running of the Oaks Stakes over one and a half miles at Epsom Racecourse on 4 June attracted a field of twenty-one fillies with Sun Cap, ridden by the Australian jockey Rae Johnstone, being one of four French challengers.
The betting for the race was unusually open with Altana (third in the Grand Critérium) and Sybil's Niece (Queen Mary Stakes) starting 8/1 joint-favourites ahead of Bara Bibi (Princess Elizabeth Stakes) and Amora (Cheshire Oaks) with Sun Cap next in the betting on 100/8 alongside Festoon and Angel Bright (Lingfield Oaks Trial).
[6] Sun Cap took the lead approaching the final furlong and drew away to win the race "with the utmost ease"[2] by six lengths from Altana with Philante taking third to complete a 1-2-3 for France.