The 22-year-old centre-back was snapped up by Bhoys' boss Neil Lennon in a £2.6million move from Dutch side FC Groningen last June.
And such has been the quality of his performances for the Hoops that van Dijk has pushed himself into contention for a place in the Dutch World Cup squad.
The cultured defender has also formed a superb central defensive partnership with the Hoops' Nigerian stopper Efe Ambrose which has played a key part in helping Lennon's lads going 18 points clear in the SPFL Premiership.
Celtic's twin defensive towers have now helped to ensure the rearguard' has remained unbreached for some 11 Premiership games stretching back through 1035 minutes of league football.
And former Celtic captain Boyd has no doubt that the axis at the heart of the Hoops' back line has been a huge part of that "solidity",
But the Parkhead favourite says these impressive defensive displays mounted by his former side have been down to a real Celtic collective effort.
A hugely versatile defender, Boyd skippered the Hoops between 1997 to 2002 and holds the distinction of having been the captain who lifted Celtic's first league title in 10 years, in 1998, and so denied Rangers a record-breaking ten titles in a row with that same championship success.
And he said: "Virgil van Dijk has to be one of the bargains of the century for Celtic. To have snapped him up for £2.6m, the way he has been performing at centre-back, has been an outstanding piece of business.
"I would go so far as to say that he is one of the best central defenders I have ever seen at such an early stage in his career. He is dominant in the air, has a great turn of pace and he is so comfortable on the ball and loves to bring the ball out from the back and build an attack.
"I think it tells a story that he is still in with a chance of making the World Cup Finals with the Dutch squad after his move to Celtic.
"They have a couple of big friendlies coming up and if Virgil can impress, given his consistency with Celtic, he will give himself every opportunity of making Brazil in the summer."
Boyd became only the second Celtic captain after Billy McNeill to lead Celtic to a treble-winning season, in Martin O'Neill's first season in charge, back in 2000/01, when Celtic secured only the third treble in their history.
Almost equally proficient in every place across a back four the former Parkhead captain was keen to stress that the current near-flawless Celtic defensive resolve has several outstanding contributors.
Boyd said: "Efe Ambrose has been a huge part of Celtic's success at the back. I think he has really blossomed this season with Virgil playing alongside him and he has cut out some of the errors that plagued him last season.
"He is just so relaxed on the ball but also has a rugged presence about him and he is a big part of their partnership at centre-back.
"Then on the flanks you have Emilio Izaguirre, who is definitely back to his best and performing with a consistency, energy and hunger that were the hallmarks of his game before he sustained that nasty injury.
"On top of that you have young Darnell Fisher, who at 19 has come in at right-back for the last four games and slotted in like he has been playing there for years."
But Boyd was also unreserved in his praise for the man the Spanish call simply "the wall" - keeper Fraser Forster.
He said: "Behind every good defence you need a good goalkeeper and in Fraser, Celtic have one who is playing at the top of his game right now. I think that for a big man he gets down exceptionally well.
"In the games with both Hibs and Kilmarnock his ability to stay focused when he has been out of action for whole passages of play, then react to make a save, has been the reason Celtic have kept clean sheets."
The 72-times capped former Scotland star has no doubt the longer the current Celtic backline stay together the better they will get.
Boyd said: "As a defence the more games you play together the better the understanding you develop and you can see that happening with this Celtic defence.
" You also have to remember that they have Adam Matthews and Mikael Lustig still to come back from injury.
"So right now this Celtic backline is about as strong as any the club have had in recent years and like I say, if they stick together they will only get better."