Having won a Grade Two at Ascot last month, the six-year-old struck at the same level for the second race in succession when landing the two-mile-five-furlong contest, which was rerouted from Huntingdon on Sunday.
Taking over matters at the penultimate fence from stablemate Josses Hill, the 4-9 favourite quickly opened up after the last to score by three and a quarter lengths.
Henderson said: "We used him up a lot last year because we never thought he would make a chaser.
"I was delighted with both of them, Josses Hill jumped beautifully out in front. The ground was probably sticky enough for both, but we have got the race in and got the job done.
"When he was a juvenile over hurdles, Guillaume Macaire said make the most of this horse as there is no improvement in him only because he lacks that scope.
"We were only just throwing him in here, throwing him in there, and now we are having to treat him like a proper good horse. I would think the Ascot Chase, then Ryanair would be the plan."
He added: "If it wasn't for Bristol De Mai (in same ownership) I would have been gagging to have a go at the King George and have a look at it. You can understand why we are not going to (Bristol De Mai is on course for £1million Jockey Club Chase Triple Crown bonus) and Ascot would appear the obvious race for him."
Winning rider Daryl Jacob was equally as delighted with the victory of the Simon Munir- and Isaac Souede-owned gelding, who was left unchanged at 6-1 with Paddy Power for the Ryanair.
He said: "He is a wonderful horse and one of my favourite horses in training. He is small, but he has got a massive heart.
"His Ascot win was probably more impressive, but the ground was very dead out there. I'm just delighted he has won."
Richard Mitford-Slade will not forget the 100-1 victory of Samuel Jackson anytime soon after the five-year-old provided the permit holder with his first winner under rules when taking the Ivor Brimblecombe Memorial Novices' Hurdle.
Mitford-Slade said: "I only got my permit 14 days ago and this is my first runner under rules.
"I farm and run an equestrian business about five miles from here. I didn't want to come too far for my first runner. I had a little bit on him."
James Bowen was another to celebrate his first victory at the Somerset track when galvinising the David Rees-trained Dream Bolt to glory in the Stables Business Park Handicap Chase.
Bowen said of the 6-1 winner: "Turning in we had plenty left in the tank, even though I was rowing away. Once he knew he could get to that horse (Coeur Tantre) he really put his head down and tried very hard."
Ride of the day
Killian Moore and Kelvingrove nearly parted company midway the two-mile-seven-furlong novice limited handicap chase, but after sitting tight the 25-year-old was duly rewarded.
Performance of the day
Top Notch was the star on show, but Our Merlin looks to still be on the up after completing a hat-trick with the minimum of fuss to set up a shot at bigger targets.
Quote of the day
Permit holder Richard Mitford-Slade's tactics to Micheal Nolan were simple on 100-1 victor Samuel Jackson: "I said to Micheal Nolan 'if you come round the bend with a bridle full then go for it'."