1879: two-year-old season Petronel began his racing career in the Middle Park Stakes, then the most prestigious race for two-year-old, over six furlongs at
Newmarket Racecourse in October, and finished unplaced behind the favourite Beaudesert. On his only subsequent start of 1879 he contested the £425 Troy Stakes at the same track and won easily from the filly Strathardle. A correspondent for ''
Bell's Life'' wrote "Petronel a tough sort of colt and he should train on, as he possesses plenty of size, good limbs and will probably prove as good a stayer as his sire."
1880: three-year-old season '' On 28 April Petronel, ridden by
George Fordham, was one of seventeen colts to contest the 72nd running of the 2000 Guineas over the Rowley Mile at Newmarket and started at odds
20/1. Despite his relatively modest form, and conflicting reports about his performances in training, he had been backed by some professional gamblers of the strength of inside information. Brotherhood started the 9/4 favourite, ahead of the
Duke of Westminster's Muncaster on 9/2, with Beauminet, The Abbot and Zealot on 10/1. Petronel was not among the early leaders as Beauminet set the pace, but moved into contention as the runners entered the last quarter mile. Entering the final furlong, Beauminet weakened abruptly, leaving Muncaster in front from Petronel and the rapidly closing The Abbot. In a "close and exciting struggle" Petronel overhauled Muncaster in the final strides to win by a head, with The Abbot three quarters of a length back in third. The Duke of Beaufort initially thought that his colt had narrowly failed to catch Muncaster, saying "ten yards farther and I should have won", before the official result was posted. Petronel had no chance to challenge for the
Triple Crown as he had not been entered for either the
Derby Stakes or the
St Leger. He returned to the track on the opening day of the
Royal Ascot in June where he finished third to Zealot and The Abbot in the
Prince of Wales's Stakes conceding fifteen pounds to the winner. On the following afternoon he won the £880 Biennial Stakes "in a canter" from Bladud, Brotherhood and Pride of the Ocean. He turned out again on the third day of the meeting and came home third behind the filly Cipolata and the four-year-old Discord in the New Biennial Stakes. In October Petronel was assigned a weight of 103 pounds for the
Cesarewitch Handicap over two and a quarter miles at Newmarket and started the 5/1 favourite. He came home seventh of the 18 runners in a race won by
Robert the Devil from Cipolata and The Star. In the
Cambridgeshire Handicap two weeks later at the same track the colt started a 50/1 outsider under a weight of 112 pounds and finished unplaced behind the four-year-old filly Lucetta. On his final appearance of the season, Petronel ran a close third to Prestonpans and Philammon in the Autumn Cup at
Liverpool Racecourse on 10 November. Petronel ended the year with winnings of £5,641 making him the fifth most financially successful horse of the year behind Robert the Devil, Bal Gal,
Bend Or and
Thebais.
1881: four-year-old season '' Petronel began his third campaign by finishing fourth behind Bend Or,
Foxhall and Post Obit in the
City and Suburban Handicap at
Epsom Racecourse on 27 April. On 31 May Petronel was assigned top weight of 124 pounds for the £500 for the one and a half mile Epsom Stakes Handicap at the same track and started the 13/8 favourite. Ridden by
Fred Archer he took the lead approaching the final furlong and won "comfortably" by three quarters of a length from
Lord Bradford's Retreat. At the Ascot meeting in June he ran three times, as he had done in 1880. In the
Royal Hunt Cup he finished third behind Peter and Sword Dance before turning out for the two and a half mile
Gold Cup on the following day. He never looked likely to win but stayed on strongly in the straight to take second place behind Robert the Devil. On the next afternoon he carried 130 pounds in the £1000 Rous Memorial Plate and won from Ishmael and Toastmaster. On 30 June, with Archer in the saddle, he added a win in the Queen's Plate (worth £200) at
Stockbridge Racecourse, beating the favourite Exeter by a neck. The death of the Duke of Beaufort's son Fitzroy Somerset, led to Petronel being withdrawn from his engagements at the
Goodwood meeting. On 14 September Petronel carried top weight of 124 pounds in the £300 Great Yorkshire Handicap at
Doncaster Racecourse and started the 2/1 favourite against thirteen opponents. Ridden by Archer, he took the lead in the straight and won a "good race" by a neck from Teviotdale with Syracuse three lengths back in third. At the same meeting he started the 4/11 favourite for the Doncaster Cup and won from Tristan. In October Petronel ran for the second time in the Cesarewitch, but carrying top weight of 132 pounds he finished unplaced behind Foxhall. At the same Newmarket meeting however he won the £300 Queen's Plate over two miles, beating Lord Bradford's Chippendale by three quarters of a length at level weight with the pair finishing well clear of the other two runners. At the next Newmarket meeting he ran unplaced behind Foxhall in the Cambridgeshire. In the £200 Queen's Plate over two miles at Liverpool on 11 November he started the 4/7 favourite, led from the start and won by two lengths from Victor Emmanuel. He ended his season at
Manchester Racecourse with a "great game" performance to finish third in the
November Handicap when conceding more than 50 pounds to the winner Gladstone. Petronel's seven victories as a four year old earned his owner a total of £2,677.
1882: five-year-old season In June 1882 Petronel made his second attempt to win the Ascot Gold Cup. He raced in second place for most of the way but was unable to make any progress in the straight and came home last of the three runners behind Foxhall and Faugh-A-Ballagh. On the following afternoon he stated a 100/1 outsider for the three-mile
Alexandra Plate and ran third behind Fiddler and Foxhall. He barely completed the course, finishing "very distressed" in a "slow canter". Despite his poor performances at Ascot he returned to winning form three weeks later when he took the £200 Queen's Plate at
Newcastle Racecourse. By this time he had developed respiratory problems, being described as a "
roarer" but he was able to win the Queen's Plate at Stockbridge for the second time. At
Brighton Racecourse on 1 August he finished third to Fenelon and Isabel in the Brighton Cup over two miles, conceding 42 pounds and 25 pounds to the winner and runner-up respectively. At some point before the autumn of 1882, Petronel appears to have enabled the Duke of Beaufort to gain possession of "The Whip", an unusual challenge trophy said to be fashioned from the tail-hairs of
Eclipse and open only to horses owned by members of the
Jockey Club. It is unclear if Petronel won the trophy in a match race or by forfeit.
1883: six-year-old season At Manchester on 16 May 1883, Petronel ran unplaced as a 20/1 outsider in the Manchester Cup over one and three quarter miles. On 22 October he finished unplaced behind
Bendigo in the Cambridgeshire. ==Stud record==