Defoe began his second season in the London Gold Cup, one in ten Furlong handicap races on the Newbury race course on May 20, during which he received a weight of 126 pounds. Starting with a quota of 8/1, he took the lead in the final and won by a length and a quarter ahead of the favorite Fearless Fire.  On July 1, he started as a favorite for a similar event on the York Racecourse and won 11 opponents with 133 pounds.  Less than three weeks later, the stallion colt was promoted to class for the Glasgow Stakes at 11 Furlongs on the Hamilton Park Racecourse and started 5/4 favourites ahead of Call To Mind (March Stakes) and Frankuus (Condé Prize). Mounted as in his previous start by Harry Bentley, he took the lead before taking the lead of the last Furlong and won by a length of Frankuus.  Defoe was then revived in class and distance and competed for the first time against older horses when he started in August in Newbury as the favourite for Group 3 Geoffrey Freer Stakes on 13 and a half Furlongs. With Atzeni in the saddle, he came close to the final and gained a three-quarter-length „comfortable shadow” of the four-year-old Wall of Fire.  In St Leger`s 241st race out of fourteen and a half furlongs on the Doncaster Racecourse course on September 16, Defoe launched the fourth choice in betting, but failed to replicate his best and finished 11th in a race where Capri won from Crystal Ocean, Stradivarius and Rekindling. Defoe (May 8, 2014 in British, Ireland; July 29, 2020 in Ireland) was an Irish thoroughbred racehorse. After winning a small race as a teenager, he won four consecutive races the following year, including the Glasgow Stakes and Geoffrey Freer Stakes. In 2018, he won the John Porter Stakes and Jockey Club Stakes, but was warmed up at the end of the year. At the age of five, he celebrated his first group 1 victory by winning the Coronation Cup and winning the Hardwicke Stakes. He remained in training in 2020, but suffered a fatal injury in July of that year.
 On September 11, on his debut at the racecourse, Defoe started Las Racecourse as the favorite for a blank race of four riders over a mile on soft ground and won with a header from the plant of the paired Bianca Minola.  Two weeks later, on the Epsom circuit, he finished second of five runners in a small race, beaten one and three quarters of a length by the Paul Cole formed Medieval. In his last race of the year, he was strengthened in class and distance for the Listed Zetland Stakes over ten Furlongs on the Newmarket Racecourse, but he ran very badly and came back in 11th place of the twelve riders, more than 26 lengths from the winner Coronet. As in 2018, Defoe started his season in the John Porter Stakes, but he failed to repeat his success from the previous year as he finished fourth in the eight finishers behind Marmelo. He continued his path from the previous year, when he played in the Jockey Club Stakes and finished second, beaten by the four-year-old stallion Communique. On May 31, Defoe launched the 11/1 in a nine-rider peloton for the Coronation Group 1 Cup over a kilometer and a half on the Epsom course. Lah colt Ti Dar took the favorite start, while the other riders were Kew Gardens, Old Persian (Sheema Classic), Marmelo, Marando (Ormonde Stakes) and Communique.