Just as Greece have been on a high since being crowned European champions last year, Turkey's third place finish at the 2002 World Cup in Japan and South Korea has created an air of expectation -- but one which is beginning to weigh heavily.

If Otto Rehhagel's Greece side win their encounter in Istanbul, they will inch closer to the top of the group while for Turkey -- who claimed just six points from their first five matches -- it could be game over ahead of their next qualifier four days later in Kazakhstan.

On paper, Turkey can boast the best record from the three encounters they have played although given what is at stake those matches could be considered irrelevant.

For the record, Turkey have never lost against Greece, winning their first ever match -- a friendly in 1988 -- 3-1 and returning from Athens six months later with a 1-0 victory.

The sides' next encounter, 15 years later and in the current qualifying campaign, ended in a scoreless draw at the Karaiskaki stadium in Piraeus last September.

Given their need for a win, Turkey - who lead the group in scoring on 13 goals -- can't afford to play for a draw.

Rehhagel said: "We must give a special performance in the matches against Turkey and Ukraine in order for us to get as many points as possible and keep second place."

Asked if a draw against Turkey would be a positive result the German added: "It would be so, because we will get to keep the two points distance. Even in terms of pure mathematics, anything is possible, even with regard to the first place."

Ukraine meanwhile have turned out to be the group's surprise pace-setters.

Formerly part of the Soviet Republic Ukraine host struggling Kazakhstan in Kiev on Saturday having stormed their way unbeaten to the top with five wins from seven games.

Observers might feel tempted to point to the presence of AC Milan striker Andriy Shevchenko -- however Ukraine, who are bidding to secure World Cup finals qualification for the first time having come close on the last two occasions, are far from being a one-man show.

Given their unbeaten record so far, it is only right that goalkeeper Alexandr Shovkovski gets some of the credit.

Shevchenko was absent for the 1-0 win against Denmark in Kiev on 30 March as Shovkovski kept another clean sheet for Oleg Blokhin's ambitious side who have leaked only three goals in seven games.

Elsewhere, the Republic of Ireland can further boost their hopes of qualifying from a tight group four with a victory over Israel -- although coach Brian Kerr will be asking his players to be vigilant until the final whistle.

Israel, who sit second in the group behind only on goals difference to France, have surprised a few of their group rivals recently by scoring late equalisers to claim a valuable share of the points.

France, Ireland and Cyprus have all succumbed to late equalisers in the last five minutes of their match against the Israelis.

Ireland will have studied their opponents carefully, and will be hoping their record of not having lost a World Cup qualifier in Dublin since October 1993 stands firm in what is effectively a game in hand over France and Israel.

Kerr, at the helm since January 2003, has only lost two of his 27 games in charge. Both were away from home, and he has reiterated the need for a home win on Saturday.

"This is a game we should win, and if we do win then it would be hard for them to retrieve the situation in the group," said Kerr.

"That makes this a crucial game, particularly from our point of view, this is an absolutely crucial game."

The same could be said for their near neighbours Scotland, whose qualifying campaign is in dire straits. Walter Smith's men have only two points from four games and face Moldova at Hampden without key midfielders Nigel Quashie and Gary Caldwell through injury and suspension.

Keeper Rab Douglas is also out injured, while Manchester United winger Darren Fletcher said despite his fears over missing pre-season he will play through the pain of a hamstring injury.

"I would be willing to take the risk this time around but only on the condition that I am not going to do too much damage," said Fletcher.

"I have a new season to think about with my club. If I tore a hamstring and was out for six or seven weeks that would mean I miss pre-season with Manchester United."