Bulgaria entertain Republic of Ireland on Saturday in a crucial World Cup in Sofia.

This is the big match in Group 8, because if Ireland win they re-take top spot and ruin Bulgaria's chances of reaching South Africa next summer. However, if Bulgaria take the win then the group is thrown wide open.

The hosts have been boosted by the return of captain Dimitar Berbatov, as well as Manchester City duo Martin Petrov and Valeri Bojinov.

Stanimir Stoilov is without striker Dimitar Rangelov through injury, but Berbatov is expected to take over and lead the line when the teams trot out into the Vasil Levski Stadion.

With the home expected to go with a 4-3-3 formation, they will be relying on Aston Villa's Stiliyan Petrov to act as their puppeteer. If he can pull the strings from midfield, like he did when the teams met in Croke Park, then they will be a tough side to break down.

The locals in Sofia, however, are excited about the return of Martin Petrov, who brings pace, width, and a superb crossing ability, which should set up plenty of chances for Berbatov, if he is afforded enough space.

There is a weakness to this Bulgarian team and it lies in their defense. Despite having a very experienced back four, they are slow and can be exploited.

Ireland have had some minor injuries this week with Robbie Keane, Shay Given, Richard Dunne, Caleb Folan, Glenn Whelan, and Paul McShane all sitting out training, but the only one's struggling amongst that pack are McShane and Folan.

With Colin Doyle and Wayne Henderson drafted in as back-up keepers to replace Dean Kiely, who walked out of the camp last week, and Kieren Westwood, who is getting married, all of the rumblings that tried to emerge have settled down.

Giovanni Trapattoni remains confident that his side can qualify from this group and is taking each game as it comes. He knows the enormity of the task before him in getting out of Sofia with all three points, but he believes in his players.

The Italian has yet to decide who will play right-back, but the early signs suggest it is a toss-up between John O'Shea and Kevin Foley, which would hand a competitive debut to Sean St Ledger at centre-back.

From there, the team really picks itself with only the fitness of Folan to worry about as he has been marked out as the one to fill Kevin Doyle's spot up front.

They are unbeaten so far in this group and have a great chance of putting more pressure on Italy for the top spot, but this will be their toughest test yet.