Having safely got through their 17th unbeaten league game since the start of the season, Celtic had the quiet satisfaction of learning that dropped points elsewhere meant their lead in the SPFL Premiership had stretched to 11 points. They are winning this title without fuss, without drama, and without missing a beat.
Can they go the entire league season without losing? If they were to get to around 30 games unbeaten that would seem likely, because there would be huge attention on it and it would seem a very tangible target for the players. The key period will be the next dozen-or-so games when they are likely to be more vulnerable to losing focus on any given day.
There were no pyrotechnics in the Perth stands - the issue of flags and banners being used to smuggle in smoke-bombs and flares had dominated the build-up - and none on the pitch either, with the exception of the wonderful goal scored by Celtic's elegant big centre-half. In the course of the 90 minutes, Anthony Stokes, Georgios Samaras, Kris Commons, James Forrest and Amido Balde were all used against St Johnstone. Their team-mate at the back gave them a lesson in finishing.
His goal was a wonder. There aren't many centre-halves who would take a ball inside his own half and even think about setting off on a slaloming run towards the opposition goal, let alone be able to execute it, but van Dijk did both. He weaved through the centre of the St Johnstone defence before delivering a toe-poked finish into the bottom corner of Alan Mannus' net. St Johnstone had kept a clean sheet against Hibs at the weekend despite playing for an hour with ten men. Here they withstood the champions for just five minutes.
Van Dijk would have faced more resistance if he'd turned up at his old primary school playground and taken on the bairns, but the timidity of the defending could not detract from the imagination and the technique he showed.
Celtic had Stokes through the middle and Samaras and Commons supporting from slightly deeper and wide. The three of them began as though they were going to have plenty of fun at St Johnstone's expense. Commons's neat footwork in tight spaces, and Samaras's dribbling, were especially troublesome.
Sanel Jahic and Frazer Wright, the centre-halves, were in terrible trouble at times. Stokes got away from Jahic and Mannus only to be forced to backtrack on himself and his eventual shot was blocked. Later his deft pass put Commons through, but Mannus blocked his effort. Samaras put an excellent chance wide with a header from a corner. Stokes had the ball in the net but Scott Brown was ruled to have been offside when he took the ball. Opinion was divided on whether Craig Thomson had called it right.
In truth it was all a bit too tame from Celtic. For all their possession there was not enough menace or ruthlessness about them. St Johnstone had been outplayed but not put away. A couple of volleys from Nigel Hasselbaink and Gary Millar had been all they had to show in an attacking sense. Neither Hasselbaink nor Stevie May were getting enough of the ball, or doing enough when they got it, to make any impression and it was a surprise when St Johnstone began the second half with a sustained spell of possession and pressure which began to make Celtic look vulnerable.
May fizzed a ball across Fraser Forster's goalmouth - there were no takers - and then when Gary McDonald squared another chance for him, May claimed a penalty for van Dijk's challenge. The camps were divided along the expected lines: St Johnstone manager Tommy Wright was sure it was a foul, his Celtic counterpart Neil Lennon was just as sure in his dismissal of it.
"I have not seen it back but I thought at the time that it was a penalty," said May himself. "He has stuck his arm out across me and stopped me. He saw me coming across and I thought it was a penalty. I guess I will need to see it again to be sure."
May was philosophical in defeat. "I don't think we were poor in the first half but we came out fighting even more in the second. Celtic are a very good side, though, and you need to be on your game for 90 minutes to get a result against them."
After the penalty call, St Johnstone came again and either Gwion Edwards or Brian Easton should have done better when both broke through on Forster. The big keeper was then worked when Edwards lashed a shot at him from another opening.
Celtic soaked it up, and actually came closer to doubling their lead than losing it when Commons turned and whipped a low shot towards the corner. Mannus reacted brilliantly to tip past the post.
The result meant Celtic had recorded their fifth consecutive clean sheet in domestic games. It was one of those days when their defenders, or at least one of them, was able to do it all.