As Wells prepared for the race at the 1978 Edmonton Commonwealth Games, Trinidad's Hasely Crawford took one look at the unknown Scot and vowed to leave him in his dust.
But Crawford's comments only served to inspire Wells, who went on to win a clutch of medals for both Scotland and Great Britain on the biggest athletics stages of them all.
Allan, now 60, said: "Here was the Olympic champion saying he was going to 'whup' me, this white Scottish guy who didn't really look like I belonged among these amazing athletes.
"But what that actually did was lift me and made me realise he respected me and saw me as a threat."
Wells picked up a silver in the final, reducing Crawford – who had won gold at the Montreal Olympic Games two years earlier – to the bronze medal.
With a large expat Scots following cheering him on in Edmonton, Wells won 200m gold and also took top prize as part of the 4x100m team.
His confidence higher than ever, he shocked the world two year later by winning gold in the 1980 Moscow Olympics 100m and silver in the 200m.
By the time the 1982 Commonwealth Games in Brisbane came around, expectations were high and the young man from Edinburgh – who started out as a triple jumper and long jumper – had a lot to live up to.
Despite a knee injury picked up in training, Wells did it again – taking gold in the 100m and 200m down under, thanks to the efforts of the medical experts and his wife and coach Margot.
He said: "Brisbane was incredible. There were thousands of Scots living there and we had great support.
"And with the team and staff around us as well as the fans, it was just like competing in Scotland, only with much nicer weather.
"I had strained my knee and didn't feel quite right. But I said to Margot I can either be here for a nice holiday or I'm here to win medals.
"In the first round, I ran flat out for the first time since the injury and I felt slow, but I made it.
"In the second round, I ran the fastest time in the Commonwealth and went on to win the semi-final and final.
"Over the last 10 yards in the 100m final I had to conjure up everything I had to beat Ben Johnson."
Like any proud Scot, Allan is thrilled that the Commonwealth Games are coming to Glasgow.
Even though he's an Edinburgh man, he feels Glasgow has already waited too long for the honour.
Edinburgh held the Games in 1970 and again in 1986, although the second occasion was more famous for a protest that made the Games something of a shambles.
The 1986 Games were boycotted by African, Caribbean and Asian countries – 32 nations in total making a stand against the Thatcher government's attitude towards British sporting links with apartheid-era South Africa.
Allan said: "For me, I always felt that the second time Edinburgh got the Games they should have instead been hosted in Glasgow.
"But when you consider what ended up happening with the boycott, this is a much better situation for Glasgow to be hosts.
"Coming off the back of the Olympic Games in London, it's going to be phenomenal.
"Glasgow deserves it. It's a great city, the biggest in Scotland and they really know how to put on major sporting events.
"And the regeneration that comes with hosting an event like this can be so important to a city."
Having won gold on the biggest stage of them all, Allan is a hero both to Scottish athletics fans and supporters of Team GB.
And while there is no denying the Olympics are the ultimate test for athletes, he insists there is something special about the Commonwealth Games.
He said: "It's more personal when you represent Scotland as opposed to Great Britain.
"That's probably down to how patriotic Scots are. The Commonwealth Games is the only time an athlete will wear a Scotland vest when competing at the top level and it means something extra to you.
"Scotland is a very special place and you don't get much more Scottish than Glasgow in my opinion."
Allan and Margot live in Guildford and Margot is coach to a number of great young athletes. Allan, who works as a systems engineer at Surrey University, hopes to be an ambassador for the 2014 Games.
And he has some great advice for any young Scots hoping to be part of the team in two years' time.
"You have to live for your athletics and remove any negative influences that will get in the way," he said.
"You have to be confident and realistic at the same time."