The son of Invincible Spirit began his winning run just 26 days earlier at Haydock and, after following up at Kempton and Leicester, a hike in the weights and a 6lb penalty could not stop him going in again.
Hajaam put up an authoritative display in the Philip Southgate Socks & Sandals Handicap under Stevie Donohoe, making all to win by two and a quarter lengths from First Quest.
The gelding is beginning to justify early faith in him when he was bought for 250,000 guineas as a yearling.
"He's improving rapidly. To think I got him beat off 62 at Kempton a month ago is amazing," said Fellowes.
"He's a lovely horse and you can see why he went for a lot of money as a yearling, but he's just needed plenty of time and I was lucky enough to give him just that and he's now really thriving.
"I didn't see him winning as well as he did, but you can't beat confidence in a horse."
He added: "I don't know what we'll do next. It's in the handicapper's hands. He won off 80 today and I reckon he'll go up close to 90.
"The November Handicap is starting to become a reality, but we'll see. He's in great form and long may it last."
Sentinel (4-1 favourite) gave Fellowes and Donohoe a double with a decisive success in the John Kemp 4X4 Centre Of Norwich Handicap.
The Sepoy gelding had failed to score in six previous attempts but made no mistake this time as he won cosily by a length and a quarter from Dream Start.
Back in sixth place was Richard Guest's 11-year-old Captain Scooby, who was making his 200th appearance, just a day after being unplaced at Windsor.
The William Haggas-trained Dramatic Queen (11-4) gave jockey James Doyle his 100th winner of the year when getting off the mark at the second attempt with a length-and-a-quarter verdict over Heather Lark in division one of the Breeders Backing Racing EBF Fillies' Novice Stakes.
David Simcock's Lady Of Shalott (12-1) made a winning debut in division two as she motored clear in the final furlong to come home two and three-quarter lengths clear of Come With Me under Jamie Spencer.
Haggas doubled up when newcomer Talaaqy (2-5 favourite) duly landed the odds for Jim Crowley in the British Stallion Studs EBF Fillies' Novice Stakes.