The rat-a-tat sequence of three Grade One races at Kempton on Boxing Day has rarely, if ever, seen a combination of high quality and higher drama to match the action that unfolded over the course of little more than an hour here on Tuesday, and the King George VI Chase won by Hewick was, appropriately, the most gripping of all.

From the first stride, when the quirky Shishkin jumped away with the field, to the final, booming echoes of trainer Shark Hanlon’s celebrations in the winner’s enclosure, this was a race, and an experience, that few in the crowd of just under 12,000 are ever likely to forget.

Related: King George VI Chase: Hewick wins after Shishkin slip – as it happened

The first gasps rose from the stand early on the first circuit as Frodon and Bryony Frost, the winners three years ago, flew several fences down the back from just inside the wings. Shishkin and Nico de Boinville then joined them for much of the next mile-and-a-half, matching strides and jumps until Frodon started to tire with around a mile to run.

Shishkin was still in front as they turned for home with three to jump and the hum from the stands started to turn into a roar. Allaho, the favourite, and Bravemansgame, were in close pursuit and the “big three” in the betting seemed to be going clear and preparing to slug it out to the line. Hewick, meanwhile, was last of the six runners, off the bit and apparently going nowhere fast, so much so that having set off at 12-1, he was matched at 549-1 in-running on Betfair.

The next twist came at the second-last, where Shishkin jumped well, only to stumble two strides later and unseat his rider, hampering Bravemansgame as he did so. The race, it seemed, was now Allaho’s to lose. But the green colours of Hewick and Gavin Sheehan, who had a least half a dozen lengths to find at the second-last, were suddenly bearing down on the leaders.

Hewick was still at least two lengths down at the last, with only the short run-in to come, but he was finishing so well – or, perhaps, the horses in front were stopping so rapidly – that he swept past with half-a-dozen strides to spare. Sheehan even had time to pull out what he described as a “Mikael Barzalona” celebration, recalling the French rider’s up-in-the-saddle delight on Pour Moi in the Derby in 2011.

That was just a hint of what was to come in the winner’s enclosure, as the unmistakable figure of John “Shark” Hanlon prepared to welcome back a horse that he originally bought for £800, having seen off better-fancied contenders from some of the biggest stables in the game.

Some of the language was as colourful as the trainer, but Hanlon’s general mood could be summed up by his shout to the crowd that “we’re not here for a long time so we’re going to have a fucking good time.” He insists too that while the Grand National at Aintree is probably the ideal target for Hewick, there is no way he is going to swerve the Cheltenham Gold Cup having won a King George.

“Turning out of the back, I said we will still be in the first three,” Hanlon said. “He is a small horse but he has such a heart.

“When you are here [after the King George] you have to go for a Gold Cup and Cheltenham will suit this horse a lot better as it is a tougher three-and-a-quarter miles. There were a lot of the other horses that had problems, and we came here fresh and had a great man on board, and that was it.

“I never thought he should be 12-1 today. It doesn’t usually happen like this when you buy an £800 horse [but] he is as tough a horse as you will find in England or Ireland.”

Sheehan admitted that in any other race, he would have been tempted to pull up on Hewick with as much as a circuit to run, but he realised leaving the back that his horse still had a lot more to give.

“I jumped two and thought, this isn’t happening,” the jockey said, “and the further I went, the more I thought it isn’t happening.

“I never felt comfortable, never got any fluency, or thought that I was going to. But he was still holding his pitch, and when I gave him two reminders, I started to feel a gear change and a new horse underneath me.

“When Nico went down, I thought I was going to be third, happy days. And down to the last, I thought the boys [in front] are gone, it was a brilliant feeling.

“Words can’t describe it, because you’re not going and all of a sudden you’re pitching in against classy horses like that, going to the last like a fresh horse. To do that was just massive.”

Hill continues climb to top

A champion of the present and a potential champion of the future produced memorable displays on the “undercard” here on Tuesday, as Constitution Hill, the best hurdler in training and quite possibly the best of all time, extended his unbeaten career record to eight races in the Christmas Hurdle, 35 minutes after Il Est Francais made all the running to win the Kauto Star Novice Chase.

Constitution Hill’s victory was not in doubt at any stage, but the 1-12 favourite looked, if anything, more impregnable than ever as he flicked over the final two hurdles with astonishing ease. He was nearly 10 lengths clear at the line, and will have one more run, at most, before lining up for his second Champion Hurdle at Cheltenham in March.

“I’ve not seen one jump better and the great secret to all these good two-milers … is the way they get from a to b,” Nicky Henderson, Constitution Hill’s trainer, said.

“We want to win the Champion Hurdle again. I’d be very surprised if we don’t [try to win multiple Champion Hurdles].”

Il Est Francais’s performance earlier on the card recalled the days when French-trained chasers including The Fellow, First Gold and Jair Du Cochet were regular winners at this meeting.

There was only one mistake in an otherwise flawless round of jumping which left Hermes Allen, the favourite, floundering in his wake.

“The dream this season is to win the French Gold Cup [in late May],” Noel George, who trains Il Est Francais near Chantilly in partnership with Amanda Zetterholm, said. “Then a King George here next year is very much what we’d be thinking, but whether he would go to Cheltenham [this season], we would have to see.

“I thought James [Reveley, his jockey] was going too quick, but he was just in his comfort zone.”

Autonomous Cloud can soar to success in National

There is plenty of rain in the forecast for Chepstow ahead of the Welsh Grand National meeting on Wednesday, but with the ground described as good-to-soft on overnight, it seems unlikely that it will be quite as much of a mud bath as is often the case.

That could give favour a classy and improving younger horse against the veterans and sloggers, with Fergal O’Brien’s Autonomous Cloud (2.50) possibly the pick of the second-season chasers.

He is closely matched with Jonjo O’Neill’s Iron Bridge on their form when first and second at Uttoxeter in March, but Autonomous Cloud has made a more promising start this season and his ability to keep finding more when required could prove invaluable over Wednesday’s marathon trip.

Chepstow 1.05 First Flow was just 4lb behind the highly-promising Boothill – a runner at Kempton later this afternoon – when returning to action at Ascot last month and will seems sure to appreciate this return to two-and-a-half mile.

Wetherby 11.50 The Same 12.25 Abbeyhill 1.00 Gazette Bourgeoise 1.35 Banteer 2.15 Kabral Du Mathan 2.45 Cornerstone Lad 3.20 The Northernlights

Chepstow 12.00 Minella Blueway 12.30 Imperial Saint 1.05 First Flow  1.40 Classic Concorde (nb) 2.10 Burdett Road 2.50 Autonomous Cloud (nap) 3.25 Showbusiness 3.55 Rocking Man

Kempton 12.45 Brookie 1.20 Sir Gino 1.55 Nickle Back 2.30 Boothill 3.09 Hidden Heroics 3.40 Lassue

Wolverhampton 5.00 Bomb Squad 5.30 One Last Hug 6.00 Completely Random 6.30 Queensland Boy 7.00 Lady Of Spain 7.30 Ice Shadow 8.00 Secret Sauce 8.30 Katar

Chepstow 1.40 A 6lb rise in the weights may not be enough to prevent the prolific Classic Concorde following up his win at Ffos Las last month. That was his fourth success in five starts and Connor Brace had more in hand than the margin of just under four lengths might suggest.

Kempton Park 1.55 Nickle Back has made an excellent start to his chasing career and the form of his six-and-a-half length second to Hermes Allen last time out was franked when the winner ran a fine race in the Grade One here on Tuesday.

Chepstow 2.10 Burdett Road was useful on the Flat and was a class above his rivals at Cheltenham last time. That was enough to make him favourite for the Triumph Hurdle in March and he should underline his Grade One potential here.

Kempton 2.30 The first running of this race as a limited handicap could well go the way of Harry Fry’s Boothill, who is up just 3lb in the ratings for the latest of his two wins in strongly-contested Ascot handicaps so far this season.

Kempton 3.09 Hidden Heroics took a while to find his form this year but Dan Skelton’s gelding ran his best race of the season to win at Ludlow last time and is more than capable of a follow-up off a 2lb higher mark.

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Kempton 3.40 Fergal O’Brien’s Lassue has returned from an 18-month layoff in impressive form and was beaten less than a length when third in a useful contest at Ascot last time. She clearly gets on well with useful conditional Jack Hogan and his 3lb claim is a futher bonus.