The Pashtun from Pakistan played 555 games of squash over a five year, eight month period from 1981 to 1986 and won them all until, finally, Ross Norman of New Zealand took him down in the final of the World Open in Toulouse.
Norman had suffered more than his fair share of defeats by the world number one from Pakistan but he had vowed that one day Khan would leave the door ever so slightly ajar and he would slip through it.
“Every winning streak will have to end some time,” Khan had said.
Every sport has known its fair share of Jahangir Khans. The Heineken Cup alone had given birth to three dynasties before Leinster got hooked on the winning habit. But times have changed.
Today, Leinster play the part of Khan and Clermont Auvergne that of Norman and the result will determine if Joe Schmidt’s side go the way of Leicester, Toulouse and Munster before them and get swallowed up by the peloton.
Lose and their Heineken Cup campaign will be all but over on the wrong side of Christmas for the first time in six seasons and there is no guarantee they would return to the summit in 2014 or in the years immediately after.
Only Toulouse of the three earlier behemoths have won another Heineken Cup since their falls from grace, which they did courtesy of a win against Biarritz three years ago. Leicester have come up short in two final defeats while Munster have yet to progress that far again.
It is a salutary lesson ahead of today’s pool five encounter with a side that would take great pleasure in doing unto Leinster as Leinster have unto them in recent times and excuse the champions from the top table.
That Clermont harbour clear designs to ascend to the throne in their place is no small thing in itself. After all, it required good teams that were on the verge of greatness to bring about those earlier changings of the guard.
Vern Cotter’s side has already started the process of chipping away at Leinster’s air of invincibility, with last week’s 15-12 win at Stade Marcel Michelin bringing to an end the province’s run of 18 European fixtures unbeaten.
To follow that up with another victory, in Dublin of all places, would be an era-defining achievement, not least because Leinster have lost just one of 24 Heineken Cup home games since the autumn of 2005.
Yet, should Leinster pull through, it would not be difficult to see them claim two more wins and a place in the knockout stages as one of the best runners-up and there is every possibility that these two could meet yet again in that scenario.
“If it ends up that way so be it, but we’re not thinking that far ahead yet,” says Sean O’Brien. “We have to go out there and do our jobs this weekend and put ourselves in that position. ”
As they did last week, Leinster will present themselves for kick-off at something less than full strength. They are vulnerable at midfield and in the second row, in particular, and the absence of some of the squad’s alpha males has automatically weakened the bench as well as the starting 15.
Clermont know this but then they knew it last Sunday as well and never looked like rolling over a side that can lean heavily on the accumulated knowledge and belief that comes with three successful campaigns in the last four years. They may have brought Leinster’s two-year run without loss to an end but it worth pointing out that Khan responded to Norman’s victory in 1986 by embarking on another nine-month run without defeat.
Champions may depart the scene, but they rarely go quietly.