MADRID, Sept. 28 (Xinhua) -- FC Barcelona face probably their toughest challenge of the season to date when they play Sevilla in the Sanchez Pizjuan Stadium on Saturday night.
Tito Vilanova's side faces a rival that has won its last two matches, which is unbeaten so far this season and which seems to have recaptured the spirit that made Sevilla a side to be feared three or four seasons ago.
Vilanova will be aware that Sevilla's last home game saw them score a second minute goal against Real Madrid and then hold on the rest of the game for a well-deserved 1-0 win. Winger Jesus Navas is back to his best after suffering ankle problems, while strikers Alvaro Negredo and Manu del Moral offer power and pace.
That will present a real threat to a makeshift Barcelona central defense, which will almost certainly be made up of Javier Mascherano and Alex Song as a result of injuries to Carles Puyol and Gerard Pique, coupled with Vilanova's apparent reluctance to blood youngster Marc Bartra.
With the 'Classico' against Real Madrid to be played in the Camp Nou next weekend and doubts over whether or not Puyol and Pique will recover in time to play, Vilanova needs to try and bed Song and Mascherano into their roles together.
They will be partnered by Jordi Alba at left back and former Sevilla defender, Dani Alves on the right.
Barcelona travel knowing that a win would once again put them 11 points ahead of Real Madrid, who play Deportivo la Coruna on Sunday and mean that whatever Madrid's result, Jose Mourinho's side will travel with at least an eight-point deficit to the Camp Nou the following week.
Barca need to sharpen up in attack and it will be interesting to see if Vilanova again kicks off with David Villa in the side or whether he puts faith in Pedro Rodriguez, who is in fine form this season and gave life to a Barca side that struggled to defeat Granada last week.
There is also a question over the form of Alexis Sanchez, who himself admitted his performances deserved a mark of just 5 out of 10 when he spoke to the press in midweek.
Finally, Leo Messi has looked slightly frustrated in recent games and Vilanova needs to ensure the best player in the world doesn't drop too deep to look for the ball. Vilanova needs to remind him Messi that he is most effective when he arrives sharp in the last 30 yards of the pitch.