October saw Twilight Son, now undefeated in five races, matched against the season's leading sprinter Muhaarar and start the 4/1 second favourite in a 20-runner field. Ridden by Ryan Moore he was no match for Muhaarar but proved the clear second best on the day, finishing two lengths behind the winner but one and a half lengths in front of the third placed Danzeno. 2016: four-year-old season Twilight Son began his third season in the Duke of York Stakes at York Racecourse on 11 May in which he carried a weight of 139 pounds. He was restrained by Sweeney in the early stages before staying on in the last quarter mile and finishing fifth of the twelve runners behind Magical Memory. At Royal Ascot in June Twilight Son started 7/2 third favourite behind Magical Memory and The Tin Man (Leisure Stakes) in a nine-runner field for the Group One Diamond Jubilee Stakes. The other runners included Gold-Fun from Hong Kong, Signs of Blessing (Goldene Peitsche) from France, Undrafted (winner of the race in 2015) from the United States and Holler (Canterbury Stakes) from Australia. Ridden by Ryan Moore, Twilight Son raced just behind the leaders Signs of Blessing and Holler before making a forward move approaching the final furlong. He overtook the French horse fifty yards from the finish and held off the fast-finishing Gold-Fun to win by a neck. Signs of Blessing was a short head away in third with Magical Memory and Suedois just behind in fourth and fifth. Candy, who was winning for the first time at the Royal Ascot meeting since taking the Royal Hunt Cup with Pipedreamer in 1979 said "He's a strong character, this one. He has a mind of his own, and after his run at York I realised he needed a lot of work and so I have been quite hard on him. That showed today – he definitely stayed on well enough at the finish!" Ryan Moore commented "I always felt that, when I was going to ask him, he was going to win. He travelled very strongly and the pace wasn't strong enough for him. It would have been better if they'd gone quicker. He's a very good colt and is getting more confident". Twilight Son failed to reproduce his best form in his two remaining races. In the July Cup at Newmarket he was in contention approaching the final