The five-year-old drew right away form his 21 rivals in the final furlong to turn the highly-competitive five-and-a-half-furlong heat into a procession.
Though the field split into two groups, the near side clearly held sway from some way out and it was Spring Loaded (12-1) who produced a decisive turn of foot to put the race to bed.
Vibrant Chords (7-1 favourite) stayed on well for second but was beaten three and a half lengths, with Justanotherbottle another three-quarters of a length away in third and Lexington Abbey a length further back in fourth.
Haynes was celebrating his biggest career success to date, and said: "I'm absolutely delighted, a big thank you to Mr d'Arcy and the owners for letting me ride him, it's brilliant.
"We knew there would be a lot of pace on and it was always going to suit him. As soon as I asked him, he picked up. It felt good."
D'Arcy said: "I told Joey he'd come alight and not to force him and he's given him a great ride.
"He had a bad draw at Chester and a stress fracture earlier in the year, but I knew there was a big one in him.
"We didn't enter him for Ayr, the ground would be too soft. Earlier in the week people were asking why I was bothering here, but I'd seen the long-term forecast and thought we'd get away with good to soft.
"I can't see much else for him now, especially as he needs decent ground.
"He could be one for Dubai or even America, given how good he is on the all-weather.
"I've tried to qualify for the All-Weather Championships twice, first time he missed out by 1lb and then he got the stress fracture last year."