SO who should the Glasgow Warriors support worry about most, as they look forward to Friday's match against Ulster at Scotstoun, at a stage of the PRO12 season in which the home team - any home team - has yet to lose?

One of the Belfast-based side's players who did so well against them in the first half of last week's league match? One of the key men who was rested for that encounter?

No. Vitas Gerulaitis, that's who. True, the American tennis player never took much of an interest in rugby, and, having been dead since 1994, is unlikely to develop one now. But the circumstances in which he uttered one of the most memorable quotations in the history of his sport are a timely reminder to anyone tempted to conclude that a home win in the PRO12 play-off semi-final is guaranteed.

Perhaps, having defeated his compatriot on 16 consecutive occasions, Jimmy Connors was similarly tempted to take one more straight victory for granted when he walked on court at the 1980 Masters. Instead, it was his Brooklyn-born opponent who won, and then, in a humorously triumphant mood, announced: "No-one beats Vitas Gerulaitis 17 times in a row."

In other words, no matter how dominant one individual or team is over another, there are never any guarantees. And, of course, the balance of forces between Glasgow and Ulster is a lot closer than that between Connor and Gerulaitis ever was: we only need to look back to the first half of last Saturday's match to remind ourselves of that.

Statistics can instruct and entertain, no doubt about that. But, in our increasing fascination with them, we run the risk of getting them the wrong way round. Supposedly the most scientific element of sport, they can take on a superstitious, almost magical aura if we accord them too much respect.

Take that stat about 100 per cent home wins during the play-offs. Now of course home advantage exists in rugby, as it does in every sport, but the individual matches which add up to that 100 per cent have no bearing on Friday night's game. The 2012 semi-final between the Ospreys and Munster, for example, is utterly unrelated to the Glasgow-Ulster match - different players, different season, different circumstances - so its outcome should have no influence on how we think about the forthcoming game.

Statistics are not static. They change with every tackle made or missed, every point scored, every result. And sooner or later a PRO12 club will produce a result that amounts to saying "No home team beats an away team time after time after time".

Something similar can be said about momentum. Having played so well in the second half four days ago, Glasgow can tell themselves that the momentum is with them - but Ulster, with those key players to come back, can equally assure themselves that this is a new game, one with no bonus point to play for and a new prize at stake. And, for momentum to be guaranteed to have an effect on a contest, both sides have to acknowledge its existence.

With so much emotion invested in big games, it's no wonder that as spectators we're desperate to read the runes and descry something in them that favours our team. The difference for players is that they can rely on their own efforts to achieve a result. And, while the Warriors will take heart from last week's victory, they know that they can win this match not by some supposed statistical certainty, nor thanks to momentum, but simply by again playing better rugby than Ulster over the 80 minutes.

AND ANOTHER THING . . .

SAM Hidalgo-Clyne's Pro 12 Young Player of the Year award is a well-deserved conclusion to a defining season for the 21-year-old scrum-half. Not too long ago he was far from being a regular for Edinburgh: now he has made a compelling case to be Scotland's starting No 9 for at least some of this autumn's Rugby World Cup pool matches.

The past year has seen one promotion after another for the Granada-born player. First he established himself as a key performer at league level, moving above Sean Kennedy in the pecking order. Then he was included in a national training squad for the Autumn Tests, and went on in the Six Nations to become firmly established as back-up to Greig Laidlaw, the Scotland captain.

Laidlaw might have got the better of the battle in the Challenge Cup final between Gloucester and Edinburgh, but Hidalgo-Clyne is becoming a stronger rival by the month. Vern Cotter may want to select his senior side for the opening World Cup match against Japan, but in that case the USA game just four days later looks tailor-made for Hidalgo-Clyne to play from the start of a Test match for the first time and show what he can do. Level-headed, a keen learner and an extremely hard worker, he has risen to every challenge so far, and will do so again when given the chance.