Paul Midgley's son of Bahamian Bounty was winning for the fourth time since switching from William Haggas' yard and jockey Paul Mulrennan feels a wind operation may have done the trick for the 9-2 winner.
"He's improving all the time and he was very strong at the line," said Mulrennan.
"The wind operation has given him a new lease of life and Paul is a master with these sprinters. His horses are flying and hopefully there's more to come from this one."
Midgley said: "I've always liked him. I would have been disappointed if 87 (rating) was as high as he was going to go.
"I think he'll get five and a half (furlongs), he's got speed and good tactical speed as well."
It was an emotional success for the Westow handler having grown up idolising Chapman, who died in 2011.
He added: "He probably knew more than I will ever know. There is only one David Chapman."
Chapman's granddaughter Ruth Carr saddled Lexington Place, but he finished unplaced.
Mokaatil shed his maiden tag at the fourth time of asking when running out a ready winner of the Theakstons Pop-Up Beer Festival 30th September Maiden Stakes.
The Owen Burrows-trained two-year-old followed up a respectable debut second at Salisbury with a cracking run to finish fourth in the Windsor Castle at Royal Ascot, but failed to justify odds-on favouritism last time out at Wolverhampton.
No such mistakes were made this time round as Mokaatil (2-5) went on to score comfortably for champion Jockey Jim Crowley, fresh from a Listed success aboard Enjazaat at this track last week.
Crowley said: "He's got plenty of early speed and he's a very quick horse.
"He did what he was entitled to do, he had the best form going into the race. He disappointed last time on the all-weather at Wolverhampton so it's nice to get back on track today."
Life For Rent (7-2) completed the first leg of a Tim Easterby double when winning the SIS Celebrating 30 Years In Racing Nursery.
The David Allan-ridden gelding was continuing his trainer's rich vein of form after My Reward took Listed honours at Chester on Saturday.
Easterby said: "He ran a good race at Carlisle last time around but he was always on the outside and had to come round them.
"We bred him, he's tough and has a very good attitude. He'll be a nice horse next year on firm ground."
Less than two hours later, Easterby was in the winner's enclosure once more as Hope Solo (10-1) ran out a facile scorer in the SIS Trading Services Fillies' Handicap.
It was a first success for jockey Danny Tudhope after a five-day layoff following an incident at Catterick which saw him unseated from his mount Wild Approach.
Zack Mayo (6-5 favourite) made it three winners from his last seven runners for trainer Charlie McBride when comfortably landing the Follow riponraces On Twitter Handicap.
The son of Air Chief Marshal quickened nicely three furlongs from home under an enterprising ride from champion jockey-elect Silvestre de Sousa and went on to score by three and three-quarter lengths.
There was a turn up for the books in the closing race on the card as Ludorum (11-4) overturned long odds-on favourite Gakku in the hands of Paul Hanagan for trainer Richard Fahey.