Racing career
1888: two-year-old season
On 10 October Enthusiast made his debut in the Middle Park Plate over six furlongs at Newmarket Racecourse and finished eighth of the fourteen runners behind Donovan.[5] At the next Newmarket meeting two weeks later the colt finished second to Royal Star in the Criterion Stakes[6] and then started at odds of 8/1 for the Dewhurst Plate over seven furlongs. Ridden by Tom Cannon he led for most of the way before being overtaken a furlong out and beaten half a length by Donovan.[7]
1889: three-year-old season
On his three-year-old debut, Enthusiast finished fourth behind Donovan, Mr Abingdon's Pioneer and Minthe in the £12,000 Prince of Wales's Stakes at Leicester on 6 April.[8] On 1 May 1889, with Tom Cannon in the saddle, Enthusiast was one of nine colts to contest the 81st running of the 2000 Guineas over the Rowley Mile at Newmarket and started the 25/1 fourth choice in the betting. Donovan appeared to be a near certainty for the race and started at odds of 20/85 (1/4.25) whilst Pioneer and Prince Solykoff's Gold were the only other horses to start at less than 100/1. Enthusiast started slowly and then settled behind the leaders before producing a strong run down the centre of the track approaching the last quarter mile. By this point Donovan had gone to the front from Pioneer but Enthusiast maintained his progress and headed the favourite inside the final furlong. Donovan rallied in the final strides but Enthusiast held on to win by a head with Pioneer three quarters of a length back in third.[9] The closing stages of the contest provoked the "wildest excitement" which was followed by an "awful moment of breathless silence" before the judge announced the result.[10]
Enthusiast was moved up in distance for the Newmarket Stakes over ten furlongs on 21 May in which started the 100/30 second favourite in a seventeen-runner field. He reportedly "cracked"[11] two furlongs out and finished unplaced behind Donovan who won "very easily".[12] In the Epsom Derby on 5 June Cannon opted to partner Baird's more-fancied runner El Dorado leaving Calder to take the mount on Enthusiast. Starting a 33/1 outsider he ran well early on and turned into the straight in second place but then dropped from contention and came home eighth of the thirteen runners behind Donovan.[13] At Royal Ascot he faced Donovan yet again in the Prince of Wales's Stakes over thirteen furlongs and finished third to his old rival, with second place going to Royal Star.[14] He returned to winning form at Goodwood Racecourse when he won the Sussex Stakes at odds of 6/4, ridden by Billy Warne.[15]
On 11 September Enthusiast, with Cannon in the saddle, started 100/6 thirdchoice in the betting behind Donovan and the highly regarded Northern colt Chittabob for the St Leger over 14+1⁄2 furlongs at Doncaster Racecourse. The Derby winner completely dominated the race and although Cannon "did all he could", Enthusiast came home fourth behind Donovan, Miguel and Davenport.[16] Ten days later the colt was dropped back in distance for the £12,000 Lancashire Plate over seven furlongs at Manchester Racecourse and finished outside the first five as Donovan won again.[17] On the last of his races that year he came home last of the four runners behind Gold, Antipas and Ayrshire in the Champion Stakes over ten furlongs at Newmarket in October.[18]
1890: four-year-old season
Enthusiast remained in training as a four-year-old in 1890. In the Ascot Gold Cup over 2+1⁄2 miles on 19 June he briefly took the lead in the straight but was overtaken in the closing stages and finished fourth of the five runners behind Gold.[19]