The French raider arrived following three second-placed finishes in Group 1 company but with proven form on soft ground combined with his front-running style, the well-backed 5/1 chance would go on to break his Group 1 duck in remarkable style.
As was the case in earlier races on the card, it paid to be prominent once more. The confirmed front-runner jumped smartly and soon found himself out in front under the hands of Aurelien Lemaitre. The French-born rider gradually began to go through the gears and the pair soon found themselves a staggering seven or eight lengths in front with two furlongs to travel.
Distress signs began to show for those in behind with the likes of 7/4 favourite Paddington, who got worked up beforehand, coming under pressure.
The Dermot Weld-trained three-year-old star filly Tahiyra emerged from the chasing group as the sole threat and although she travelled nicely throughout the mile contest, it quickly became apparent the winner was out in front.
Big Rock's lead continued to grow as he kept up a relentless gallop at the head of the affairs and members of the crowd quickly realised, they were about the experience a truly stunning equine display.
Those in behind could never land a blow and the winning margin was a commanding six lengths crossing the line. Jerome Reynier's Facteur Cheval (14/1), runner-up to Paddington in the Sussex Stakes, stayed on nicely from off the pace to nab Tahirya for the second spot and in the process ensured it was memorable for France.
Lemaitre, who had plenty of time to celebrate up in his irons before crossing the line, said: "It's amazing, to win today on Champions Day. This horse has a very good pace, he loved the ground, it was perfect for him today."
He added: "That was very easy. He loved the ground today. He's a professional horse, he loved the soft ground and had very good pace and a great turn of foot. It is fantastic to win a Group 1 at Ascot and I'm very happy."
Trainer Christopher Head, who was saddling his first UK winner, said: "It's incredible, this horse is really impressive and I'm really happy for the owner because he has done tremendous work with the breeding and this horse is the pinnacle of the breeding system.
Today was pretty much the best mile of the season and seeing him win this way is crazy, pretty much the aptitude for the ground has done a lot too. We need to discuss with the owner [about whether he will stay in training] and Leo decides what we do....[owner interjects positively]....he stays in training.
It's a long-term relationship [with jockey Aurelien Lemaitre], he's been carrying a lot of confidence into young people, and I thank him a lot for this and Aurelien and I are going to give 100% of ourselves in this project."
