Guest Of Honour stepped up on his third place in the race 12 months earlier to win the Fred Cowley Summer Mile at Ascot.
Marco Botti's runner, for whom the trainer had planned a tilt at this race for some time, sat in midpack in the early stages as The Rectifier set a fair pace from the front with Empire Storm upsides.
Fergus Sweeney asked The Rectifier to quicken up coming off the home turn, but he was never able to shake off his pursuers and it was Mull Of Killough down the outside and Guest Of Honour, who had been switched towards the inside of the track, who drew up to fight out the finish.
Guest of Honour had to be asked for everything by Martin Harley, but he always just looked to be holding the upper hand and kept on to score by half a length.
Godolphin's Long John kept on for third place, with Producer, whose chance was seriously compromised by a slow start, a never-nearer fourth.
Botti said: "I was so pleased the rain stayed away and he's shown he's now back to his best. "He was unlucky in this last season - now we can look towards the Celebration Mile.
"Fast ground is very important to him, as he just can't handle the soft. He's an old-fashioned summer horse, but I need to find races here, as his owner (Giuliano Manfredini) doesn't like campaigning him abroad."