Last year's Stayers' Hurdle hero won on his seasonal return at Newbury and was due to run at Ascot last month, but testing conditions ruled him out on the day of the race.
Trainer Emma Lavelle was not concerned about the change in plan and Paisley Park travelled beautifully through the race, with Aidan Coleman keeping him in a handy position throughout.
Summerville Boy, stepping up to three miles for the first time, tried to make all and he was still in front as they turned into the straight.
However, Coleman knew what he had under him and on the run to the last, Paisley Park began to make ominous progress.
He jumped the last cleanly and the 4-6 favourite won by a length and a quarter, with Summerville Boy in second and 50-1 chance Lisnagar Oscar third.
Coleman told ITV Racing: "This horse isn't slow, but we've gone slow today and it turned into a bit of a sprint, so I knew I was going to have to get stuck into him at some point.
"Usually I get to the front way too soon, but today I got to the front at the last and I thought that was perfect.
"He's just brilliant, he's gone round in second gear and he's an absolute pleasure. I'm just delighted to be associated with him.
"I've waited for a horse like this, better riders than me have never found one as good as him."
Paisley Park was winning the race for a second successive year and Lavelle was delighted to see him strike gold again.
She said: "He doesn't hit the flat spot the way he used to.
"I think he was as professional today as he has been. I think he is getting better and I think I love him. It is brilliant.
"It is not just the pressure for the yard and Andrew (Gemmell, owner), but you feel you have the pressure of everybody rooting for him and you just want to deliver. He loves it and we are loving having him.
"He is not a slow horse himself and he is a stayer that has got pace. If I'm honest, watching it I enjoyed it a bit more than some of the other races I've watched with him.
"I thought that was as good a performance as I've seen from him - how he jumped and travelled.
"It was the right decision to miss Ascot. I'm saying the ground here was easy ground as it was definitely testing.
"He carried his penalty and If The Cap Fits did too. It was a proper test today, new horses up against him and he has come through the test well."
Summerville Boy could well take on Paisley Park again at the Festival, with Tom George pointing to the Stayers' Hurdle as the "obvious" choice.
He said: "He has run well. He made two mistakes when we didn't need to, though I'm not saying that made a difference to the result.
"At the end he is only a length down and he was coming back - there is no doubt about that - so we are heading in the right direction.
"I just thought we would try to sprint off the home bend and catch him (Paisley Park) out a bit and we did catch him flat-footed for a minute, but it was a good run.
"There are no problems with the three miles. There are no plans yet, but I thought that was the obvious route (Stayers' Hurdle)."