Loeb has two races left to overtake Gronholm in the standings

Loeb, seeking his fourth successive world title, starts the penultimate round of a knife-edge season four points adrift of the Ford driver.

The event starts with a super-special stage at Stormont on Thursday night before heading to its Sligo base.

Three days of action will follow on both sides of the Irish border.

Should Loeb fail to score points for the fourth time this season, Gronholm will need to finish only second in the inaugural Irish WRC event in Sligo on Sunday to clinch his own third title.

However, the odds are that the battle will go down to the wire in the muddy Welsh forests in the final Rally of Britain next month.

Loeb cannot afford another mistake like the one in Japan three weeks ago where he crashed out after Gronholm had already retired from the event.

Fighting for world titles in both the drivers' and manufacturers' series is a great position to be in Marcus Gronholm

"The overall result in Japan leaves us in the same situation we have been in for some events now. We've absolutely got to win," said Loeb.

"We're still very much in with a shout, but we have very little room for manoeuvre," said Loeb.

The event, the third new rally on the 2007 calendar, straddles north and south with a total of 20 stages over the three days.

Ford need score only three points to defend their manufacturers' title since they lead Citroen by 34 points with 36 still to be won.

"I'm really excited about the end of the season," said Gronholm, who will retire at the end of this season.

"Fighting for world titles in both the drivers' and manufacturers' series is a great position to be in and to win both would be the most fantastic way to end my career.

606: DEBATE Give your thoughts on this week's Rally Ireland

"Of course, it's not that easy and things change quickly in this sport so nobody in the team is taking anything for granted," he added.

Essentially an asphalt rally, the winding roads roads pose a real challenge with plenty of bumps and farmyard mud adding to hazards in the wet.

Loeb, Gronholm and the Finn's team-mate and compatriot Mikko Hirvonen have all competed in Irish rallies this season to get a feel for conditions in the country.

Hirvonen, who was in action at the Cork International in September, believes the Irish event will be "the most difficult rally of the season".

"Nobody knows what the weather will do. It could be cold overnight so a combination of ice and narrow, bumpy roads would be extremely difficult," said Hirvonen.

Indeed, the forecast is for wet and cold conditions over the weekend.

Irish drivers Kris Meeke, Eugene Donnelly and Gareth McHale will hope to make an impact on their home roads.