Dropped to a mile, the Sheikh Hamdan-owned son of Dawn Approach raced towards the rear of the field through the early stages, as Ancient Spirit took the seven runners along.
He made progress from the three-furlong pole and once switched wide for his run in the straight, he only took a stride or two to pick up the leaders, without Chris Hayes having to get overly serious.
He's back - the very smart Madhmoon is off the mark for the season with all roads to the QIPCO Irish Champion Stakes this time next month @LeopardstownRC @IrishChampsWknd— Racing TV (@RacingTV) August 15, 2019
Results ➡ https://t.co/glajGV55GR pic.twitter.com/y1d2My9p5z
Zuenoon made late headway to take second, a length and a half behind the 4-7 favourite.
Prendergast said: "He did it well. The run will do him good, because he's fairly burly looking.
"He'll come on a lot and the Champion Stakes is his next outing. After that, if he puts up a good show, he'll go to Ascot for the Champion Stakes there. We'll see how he gets on here first.
"I thought he did it well. He stumbled out of the gate and just got a little bit unbalanced in the first furlong, then he settled in and raced nicely after that.
"He travelled well, quickened up well and won without a smack."
When asked if 10 furlongs could be the winner's optimum trip, Prendergast said: "Well he was second in the Derby over a mile and a half and you can't argue with that as he's only beaten half a length in the English Derby.
"On the day any of the first four or five could have won and I'm sure some very good horses will come out of the Derby."