Alan Massie: When it comes to comparing the greats, few can boast of being undisputed number one

A few seasons ago, Selkirk supporters were invited to play the same sort of game, and so week after week the match programme featured our selections, provoking more argument about every position except number ten, where John Rutherford reigned supreme.

The longer you live, the more memories you accumulate, the more difficult the game becomes. Would Muhammed Ali have beaten Joe Louis? Who knows, though we can argue the merits of each enthusiastically.

Is Roger Federer, Rafa Nadal or Novak Djokovic the supreme tennis champion? Or would John McEnroe have seen them all off? When Dan Maskell, for so long the Voice of Wimbledon, cast back over his memories, he went back to the 1920s to name the American Big Bill Tilden as the best. And only a couple of weeks ago I heard Bob Willis name Viv Richards the greatest of all batsmen - "sorry, Bradman fans", he added.

Writing after last week's magnificent and extraordinary Heineken Cup final, the former England and Lions centre Will Greenwood went out on a limb to declare that Brian O'Driscoll was the greatest Irish rugby player of all time. O'Driscoll, at best three-quarters fit, had had a bad first half in that final against Northampton, once being cut down in sight of the try-line by Ben Foden and being twice beaten on the outside by Foden again. But in the second half he was at the heart of Leinster's astonishing come-back, even though the plaudits went to Jonny Sexton.

Greenwood admitted that his choice would not please his father, Richard, England wing-forward of the 1960s, who regarded Mike Gibson as the greatest of them all.

An awful lot of us agree. "Peerless" was the adjective usually applied to Gibson, the complete player, master of all the arts and crafts of the game. Yet even Gibson's warmest admirers must admit that O'Driscoll is at least his peer. Gibson was arguably a more complete player than O'Driscoll, a better passer of the ball off either hand, for example. Yet O'Driscoll has been the inspiration of the most successful sides in Irish rugby history, the man who rescues matches that seem to be slipping away. He has been a more dominant and influential player than Gibson was; also a great captain, a role in which Gibson was uncomfortable.

So what can one say? Perhaps the best answer is one given by an old St Andrews caddie more than 80 years ago.Asked which was better, Bobby Jones or Young Tom Morris, he replied - dourly, one supposes -, "baith o' them played pairfect gowf."

When Bill McLaren compiled his team of teams, there was some surprise at his selection of England's Rob Andrew at fly-half. Fine player, we agreed, but better than Barry John or Phil Bennett, Cliff Morgan or Jackie Kyle? Now there are many ready to say that Dan Carter is the greatest of all number tens - even though we may add the rider that it is a dashed sight easier to play behind the All Blacks forwards than most international packs.

Those of us old enough to remember Kyle are, however, reluctant to give the palm to Carter. What one can certainly say is that an Ireland midfield of Kyle, Gibson, O'Driscoll would be hard to match.

We can argue such questions happily, and intensely, for ages. Meanwhile, this long and demanding rugby season is at last approaching its end with the Magners League final between Leinster and Munster and the final round of the IRB Sevens at Murrayfield. Can Leinster raise themselves for yet another huge effort, or will Munster cast aside their unusual European failure to reassert themselves at the top of the Irish pecking-order? One has the feeling that this encounter will prove a battle of wills between O'Driscoll and Paul O'Connell, both Lions' captains.

Finally, the Murrayfield Sevens give Graham Shiel's squad - the strongest he has been able to select - the chance to end what has generally been a disappointing season for Scottish Rugby on a high. There are two words of advice he might give his squad, both, as it happens, from famous football managers. The first is from Johan Cruyff: "When you have ball, make the pitch big; without it, make the pitch small." The second is the only sentence that on one big match occasion Brian Clough spoke to his Nottingham Forest team. He chucked a ball into the dressing-room and said: "There's a ball; now go out and play with it."