With only five points separating the top four sides, the two qualification spots are still very much up for grabs.

Leaders Poland travel to third-placed Portugal, whilst second-spotted Finland face a trip to Serbia, who lie fourth.

Euro 2004 runners-up Portugal will be looking to get revenge on Poland after a 2-1 defeat in the reverse fixture 11 months ago.

A win for Scolari's side would put them in control of the group as they have a game in hand on both Poland and Finland. Both teams have dropped key points away to Armenia of late, leaving the group wide open for Serbia, Finland and even Belgium still have a chance.

Manchester United winger Cristiano Ronaldo will be fresh following his three-match domestic suspension for headbutting Portsmouth defender Richard Hughes.

Ronaldo's club colleague Nani has been recalled by Scolari for the clash along with Benfica's Petit, Atletico Madrid's Maniche and Werder Bremen's Hugo Almeida.

Chelsea's Ricardo Carvalho is still out with a knee injury, which has kept him sidelined since April. Real Madrid's £20million summer signing Pepe is also unlikely to play due to thigh tear but has still joined up with the squad.

Scolari is likely to call on Jorge Andrade and Fernando Meira to cover his defensive absentees.

Poland head to Lisbon knowing a draw will keep them in control of their own destiny despite losing in Armenia in their last group match.

Coach Leo Beenhakker has opted for stability, calling up no debutantes and naming six back-up players for the vital match. Playmaker Lukasz Gargula makes a return after recovering from an array of injuries.

Finland travel to Belgrade buoyed after picking up wins in their last two home games - against Belgium and Kazakhstan.

Coach Roy Hodgson faces a selection headache with Toni Kalio, Aki Riihilahti and captain Jari Litmanen absent. Finland do have some good news though with the return of midfielder Mika Vayrynen.

Serbia will be without Schalke defender Mladen Krstajic who has strained knee ligaments but welcome back Nikola Zigic who is expected to be fit. Serbia boss Javier Clemente has called up 20-year-old FK Partizan Zoran Tosic as his only newcomer.

The other scheduled match between Azerbaijan and Armenia has been cancelled due to the ongoing conflict between the two nations. UEFA has given both teams zero points as they refused to agree a venue for the upcoming fixtures.