Spring

During the winter of 1908–1909, Minoru made exceptional progress, and although the King's racing manager, Marcus Beresford, was initially sceptical, Marsh decided to train the colt for the Classics. The cold weather early in the year delayed the preparation of many horses, including Bayardo, but the lightly-made Minoru took little work to reach peak fitness, giving him an advantage over most of his rivals.^[6] After performing impressively in a private trial race, Minoru made his debut in the Greenham Stakes at Newbury on 31 March and won from Valens under top weight of 136 pounds.^[7] In the 2000 Guineas at Newmarket on 28 April he started at odds of 4/1 against ten opponents and was regarded as the chief danger to the favourite Bayardo. Ridden by Herbert Jones he raced prominently before accelerating through a narrowing gap^[8] in the closing stages and won easily from Phaleron and Louviers, with Bayardo fourth, in a race record time of 1:37.8. According to press reports the victory was greeted with "intense enthusiasm".^[9] Minoru was given very little work by Marsh before his next run in the Derby.

Summer

Minoru with Herbert Jones up in the Winner's Circle at Epsom. Painting by Alfred Charles Havell

At Epsom on 26 May, Minoru started at odds of 7/2 in a field of fifteen, with Bayardo and the American-bred Sir Martin, who started favourite, being seen as his main rivals.^[10] The crowd was smaller than usual on account of heavy rain on the morning of the race, but the King and Queen were in attendance.^[11] Minoru broke slowly on the inside but recovered quickly and by the beginning of the turn into the straight was in fourth place behind Louviers, Brooklands and Sir Martin, and just ahead of William the Fourth. At this point the race changed completely as Sir Martin, who had been traveling extremely well, stumbled in close quarters and lost his rider, badly interfering with William the Fourth.^[12] In the straight the race developed into a match between Minoru and Louviers who raced together throughout the last two furlongs, with first one and then the other appearing to have the advantage. The two colts crossed the line together, just ahead of William the Fourth who finished very strongly after recovering from the earlier incident, and looked an unlucky loser.^[13] After a long delay, the judge announced Minoru as the winner by a short head from Louviers, many of whose supporters were convinced that he had won.^[14] Valens finished fourth and Bayardo fifth. The victory for the "Royal" colt provoked "the wildest scenes of enthusiasm ever known in England",^[13] including a mass rendition of the National Anthem as the King led his horse to the winner's enclosure.^[15] Minoru himself was "swallowed up" by a crowd of supporters, several of whom attempted to obtain souvenirs by pulling hairs from his mane and tail,^[16] while his owner was informally congratulated with cries of "Good for you old sport!" and "Well done Teddy!".^[17] Minoru's victory was the first in the Derby for a reigning British monarch.^[18] The King received many congratulatory telegrams, his favourite reportedly being one which arrived from Argentina and read: "Minoru, England. Congratulations from your father– Cyllene."^[19]

Minoru followed up his win at Epsom by running in the St. James's Palace Stakes over one mile at Royal Ascot, in which he started at odds of 1/3 and won from The Story and Blankney II.^[20] Minoru was then sent to Goodwood on 29 July for the Sussex Stakes, another one mile race which at that time was restricted to three-year-olds. Minoru carried 134 pounds and won very easily from his two opponents, Prester Jack and Verney.^[21]

Autumn

On 8 September Minoru attempted to complete the British Triple Crown in the St Leger at Doncaster. Bayardo had meanwhile won four successive races including an easy win over Louviers at Sandown. Minoru started second favourite and finished fourth of the seven runners, six lengths behind Bayardo, who won from Valens and Mirador.^[22] Minoru had little luck in running, being unable to obtain a clear run along the rails, but appeared to have been well beaten on merit.^[23] Herbert Jones offered no excuses, and admitted that in view of Bayardo's superiority, Minoru had been "a lucky animal" to win the 2000 Guineas and Derby.^[24] On his final start of the season, he was sent to Newmarket in October for the Free Handicap, in which he defeated the filly Electra, the winner of the 1000 Guineas and Epsom Oaks, by a neck. As Jones had been injured the previous day,^[25] Minoru was ridden on this occasion by Danny Maher, who was presented by the King with a jewelled scarf-pin in recognition of his success.^[26]

Minoru's performances in 1909 was the key factor in his sire Cyllene being the 1909 Leading sire in Great Britain & Ireland. His prize money of £15,246 placed him second to Bayardo on the list of leading British money-winners.^[27]