Dorus de Vries’ Celtic career was limited to just 15 appearances in his three seasons at the club.
But he played his part in league title wins and back-to-back Trebles.
As the Hoops gear up for an assault on 10-in-a-row – and await news on when their 2019-20 Scottish Cup campaign will be revived to give them a pop at a fourth Treble on the trot – de Vries is well placed to assess their prospects.
He has witnessed the relentless pursuit of domestic success from inside the Celtic dressing room, and knows what makes it tick.
Signed by Brendan Rodgers in 2016, the 39-year-old Dutch goalkeeper saw first-hand the leadership qualities of Scott Brown and the talent of players such as Callum McGregor, James Forrest and Odsonne Edouard.
De Vries retired after leaving Celtic a year ago, and has no doubt that the Hoops will reach the coveted 10 this season.
Now retired and living back in Holland, the former Dunfermline, Swansea and Nottingham Forest No.1 told The Sunday Post: “I’m not in Glasgow, but I can still get a feeling for what’s going on, and what it’s all about.
“Celtic’s preparation is well under way, and I know the pre-season training camp will be professional, intense, detailed and enjoyable.
“At this stage, especially after having a four-month lay off due to Covid-19, the players will be desperate to play competitive football again.
“Scott Brown will be the example for the rest to follow. He is the ultimate winner and a great captain for the club. He has the respect of the dressing room, and that is vital.
“He has led the team to many successes , and he will not want that to stop.
“This season’s title is the one everybody is talking about and the desire to win it will be unbelievable.
“I say that because I’ve been there, and know what the attitude is like at the club.
“When one trophy is won, there is a lot of happiness and satisfaction. There is also a short celebration.
“But then the focus immediately moves on to what is next. ‘What do we need to do to win the next trophy?’. And so it goes on and on.
“They are never satisfied, and that is a good thing. That’s what has made them so successful and why they have won 11 domestic trophies on the trot. I’m pretty sure there will be more.
“Callum McGregor is always a vital player. I rate him very, very highly.
“He is technically excellent, and also has great awareness on the park. His game intelligence is exceptional and he carries out the tactical instructions perfectly.
“He is also very level-headed. He just wants to keep improving, always out on the training pitch wanting to get better and better.
“Brendan Rodgers said that Callum is a coach’s dream, and I can totally understand why he made that statement.
“You only need to tell him something once, and Callum has the intelligence to carry out the instruction to the letter.
“James Forrest is another player that I rate highly. For a wide player to score so many goals tells you what he has in his game.
“He can create chances from wide areas for his team-mates. But he is also effective at coming inside and linking the play inside the penalty box.
“Full-backs really struggle to contain him.
“When the likes of Callum and James have possession, it must be a dream for them to have someone of the calibre of Odsonne Edouard as their No. 9.
“He came to Celtic as a young man and his game has developed to a very high level.
“The way he stays calm and focused in games, and when he has chances to score, really impressed me.
“You just know that if you give him the ball in the box, then there at least an 80% chance he will score.
“He also has wonderful game intelligence. He wants to be coached and wants to learn.
“It does not surprise me that clubs from England and abroad are interested in him. He is special.”
The Celtic goalkeeping position is a situation that needs to be resolved.
With Fraser Forster back at Southampton, and Craig Gordon signed by Hearts, Scott Bain is the only keeper in the squad just now with high-level experience.
De Vries said: “I worked with Scott and he is very talented. He never let Celtic down.
“The club will want to add to that position, and goalkeeping coach, Stevie Woods, will be on the case. He is an excellent coach and knows the goalkeeping market very well.”