With a total prize fund of £21,000 up for grabs, the concluding race of the six-race card was the most valuable and a quality field of 11 sprinters went to post.
Our Lord, already a three-time winner this season including two triumphs over the course and distance, was the 7-2 favourite to add to his tally and while Storm Melody lunged late, the line came in time for Attwater's charge as he clung on by a neck.
Attwater said: "That was great. David said the horse carried him to the front between three and two furlongs out and then he's probably ended up in front a bit too soon.
"But he obviously handles the track and a bit of cut in the ground well and he dug deep to get the win.
"He started off this year rated 59 and he's won this off 82, so he's had a brilliant season.
"To win four races and a nice prize at the end of it is great and given he handles softer ground, we could run him again if he's telling us at home he wants to go again."
Attwater and Egan had earlier struck gold with Our Lord's half-brother Delagate This Lord, who completed his hat-trick in the PK Building Handicap.
After failing to get his head in front in eight starts for Bill Turner, the three-year-old appears to have been sparked into life since joining Epsom-based Attwater earlier in the year.
He made a successful debut for his new trainer at Newbury in June and having followed up over this course and distance last month, he was the 2-1 favourite to make it three on the bounce.
Delagate This Lord made a tardy start, but soon found his stride and came home a length and a quarter clear of Bellevarde.
"This is the second time this year they've won on the same day, which won't happen too often with brothers," Attwater added.
"This horse had been running over a bit further before he came to us, but from the first time we galloped him it was obvious he had a lot of speed.
"I was a bit worried about the ground beforehand as I definitely think he's better on better ground, but his class got him through I think.
"We'll only run him again this year if we can find some good ground for him. He's already won three, so I'm sure his owner would be happy to have him home for the winter and we'll bring him back next year.
"If he makes the normal improvement from three to four, he should be a sprinter we'll have a lot of fun with."
The Ron Hodges-trained Evening Starlight was a 12-1 winner of the first division of the Bristol Conservatory Upgrades Handicap under Steve Drowne.
There was a thrilling conclusion to division two, with Robert Winston guiding Roger Teal's 8-1 shot Langley Vale to a nose victory over Time Medicean.
Ralph Beckett and Hector Crouch combined to land division one of the nursery with 3-1 shot Jim Rockford, while Nigel Tinkler's Roundhay Park made the long journey from North Yorkshire worthwhile with an assured success in division to under Tom Eaves.
"He's a very nice horse," said Tinkler.
"Whether he'll run again this year, we'll see how he is when we get him home.
"He's a horse with a future, I hope."