Rogier was wearing an inflatable orange crown. The three men standing just in front of him were sporting orange dressing gowns, and as for orange novelty wigs - well, there were too many to count. For an hour yesterday afternoon, one side of the Conference Centre was Holland, NW10. The other side, and most of the middle, was Inger-land.
There were almost 2,000 people there in all, turning the hall into a raucous cauldron of colour and the sort of chants more suited to the famous football stadium next door. And all to see two men throw darts, in a match that was conceived and sold like a title unification fight in boxing.
Darts, like heavyweight boxing, has had more than one world champion for most of the last decade - not that much of Britain has really noticed. Phil Taylor, a pub landlord from Stoke, who throws his arrows on satellite television, is reckoned by many to be the finest player in history.
In Holland, though, they do not get to see BSkyB, and the 400-odd orange- clad fans who turned up yesterday would not hear of defeat for their man, Ray "Barney Rubble" Barneveld. "To be honest," one of them said, "until this match was announced, I had never heard of Phil Taylor."
The pair's coming together in combat yesterday had been brokered by Barry Hearn, and went out live on ITV, the station's first darts broadcast for 14 years (unless, of course, you count Bullseye).
No detail had been overlooked as Hearn tried to push the hype to the limit. Smoke machines added great gusts of fog to the haze that had already been stoked up by several hundred Bensons and Players. There were disco lights, loud thumping music and girls in swimsuits with the flags of England and Holland. And from the middle of all this emerged two podgy gladiators about to do battle with six lumps of tungsten.
They may call Barneveld "Barney Rubble" but in truth, his build is closer to Fred Flintstone's pet dinosaur, Dino. But at least he has height on his side to flatten out the worst of his spare tyre. Taylor, several inches shorter but every bit as heavy, is one of the unlikeliest sporting heroes you could imagine. Brilliant he may be, but you will never find a picture of him on your daughter's bedroom wall.
The chanting rose to a crescendo as the two players threw out their practice darts, but immediately cut to pin-dropping silence the moment the clock above the board started to count down from one hour. The two men would be playing for 60 minutes, 501 a leg, finishing on a double or - for a real flourish - with the bull. Within three minutes Barneveld was one leg up, thudding a dart smack into the middle of the board.
But Taylor was just warming up. Soon, he was hitting the tiny space of the treble-20 box time and time again, and when it came to hitting the closing doubles, he was all but faultless. The cold-blooded accuracy his podgy publican's fingers coaxed out of the darts was astonishing.
By half-time in the match, when ITV went to a commercial break, the match was in effect all over. At 9 legs to 4 up, Taylor spent the time dancing, or rather wobbling, happy little jigs around the stage, while Barneveld, with his chin in his chest, was as subdued as any of the men and women in the orange novelty wigs.
But by the end even they were applauding as Taylor produced yet another finish with three exquisite flicks of the wrist. The final score was 21-10, little short of a humiliation for Barneveld. "Boem slopen" indeed.
Rogier Gerritzen was shell-shocked. "I've been watching darts for years on TV," he said, "but I've never seen anyone play darts like that.
"I've never seen anyone hit so many high-score finishes. Whenever you thought he couldn't possibly do it again, he did. It was marvellous."
Fierce rivalry, an atmosphere that could blister the paint, and magnanimity in defeat - all on an afternoon when the standard order at the bar was not a pint, or even a round, but a trayful. If the same is true after the next big event at Wembley a week on Wednesday - when England meet Scotland in a certain Euro 2000 football play-off - it will be little short of a miracle.