But should Celtic somehow find a way to overcome a 3-0 deficit away to Juventus tomorrow night, Robertson believes it should be considered the greatest result in the club's history; even better than the night they became European champions in Lisbon in 1967.
The former Celtic assistant manager is probably on safe ground making such a bold proclamation. After all, the Italian champions are not in the habit of gifting goals to the opposition. Only once this season have they conceded three at home – to Internazionale in November – and that was a result that brought their remarkable 49-game unbeaten run to an end. Celtic, then, are up against it to say the least.
Not only must Neil Lennon's side score at least three times, they must also shut out the Italians just to take the tie to extra-time. That won't be easy given Antonio Conte's side have scored in every home match this season bar a goalless draw with Lazio in November. In that context, Robertson believes progression for Celtic would deserve to be hailed as the finest moment in the club's 125-year history. "It's unlikely but this is a game of football and anything can happen," said Robertson. "I don't think anyone would have tipped Juventus to win 3-0 in Glasgow.
"It would be nice to think that Celtic could over there and do something. If they did that then that would be the greatest result in the club's history. To go 3-0 down in the first leg and then come back from Turin going through? I don't think too many people would argue with that being the biggest result they have had.
"The Barcelona result at home [when Celtic won 2-1 in the group phase earlier this season] was the second best in the club's history because the Lions came back from Lisbon with the trophy. But, I mean, they didn't have to come back from 3-0 down did they? For Celtic to come back from Italy being through, well, they would want to be giving Neil a knighthood."
Lennon is unlikely to be kneeling before The Queen any time soon but Robertson has still been impressed with his former player's immersion into management. "People usually build up to managing Celtic and the pressure on Neil was massive," said the man who won the European Cup with Nottingham Forest in 1979 and 1980. "For him to come in and do what he's done in his first job is incredible, really.
"When he played for us he was always a very intelligent boy, even though he had his escapades, but he knew his football so I thought he could go on and do this job. It just shows you the job he's done that the other first-timers who tried it – really big names like Liam Brady and John Barnes – didn't succeed. They were great players but management is a different kettle of fish.
"I always thought he could manage a side but we have all got little foibles. Neil has had a lot to contend with but he has come through it and to get them into the last 16 has been incredible."