The leaders are anxious to prove that their first home defeat of the season, against Atletico Madrid last weekend, was a temporary blip rather than evidence of a more serious decline in form. A defeat in Zaragoza would also hand the initiative in the title race to Real Madrid, who are four points behind and play tomorrow.
Barcelona have not won at Zaragoza since 1997 and the home side are seething over refereeing decisions they claim contributed to their recent league defeats at Albacete and Real Madrid. As a protest the club are allowing the distribution of 8,000 red cards, which will be brandished by home fans when the two teams step on to the pitch.
"It's clear that the tension and controversy surrounding the match make it an even tougher game for us," said the Barcelona midfielder Xavi. "The only thing we want to do is to put in a good performance and make sure we win so that we maintain our lead in the standings."
Barcelona's Portugal midfielder Deco returned from midweek international duty with a minor back injury and the new signing Demetrio Albertini or Under-21 international Andres Iniesta will deputise if he fails to recover in time.
Real made it six wins on the trot with their somewhat flattering 4-0 victory over Espanyol last week but face a true test against Osasuna. Real have not won on their last four visits to El Sadar and can be assured of a hostile reception.
With Luis Figo suspended, the new signing Thomas Gravesen is set to partner Guti in the centre of midfield, with David Beckham on the right. Once again there is little sign of the coach Wanderley Luxemburgo making space for Michael Owen in the starting line-up.
In Italy, back-to-back defeats for Juventus have left Milan breathing down their necks so the Serie A leaders will not be relishing the prospect of tomorrow's match at third-placed Udinese. Losses against Sampdoria and Palermo have slashed their lead at the top from eight points to two.
Tomorrow, Milan continue their pursuit of Juventus with a visit to Reggina. Milan will be lacking their midfielder Andrea Pirlo, who injured his knee during Italy's midweek friendly against Russia.
Reggina will be aiming to pull off another upset at their Granillo stadium, having already beaten Juventus and Roma there this season.
BEST IN EUROPE THE INDEPENDENT INDEX
Who is the best player in Europe? And the best team? And the best league? Each week we hope to provide answers. The charts for best players and teams are compiled from the votes of experts throughout Europe.
EUROPE'S THREE BEST PLAYERS THIS WEEK WERE...
1 Zinedine Zidane (Real Madrid) Back to his best
2 David James (Manchester City) Thwarted Chelsea
3 Andrei Shevchenko (Milan) Rescued title hopes
EUROPE'S THREE BEST CLUBS THIS WEEK WERE...
1 Atletico Madrid Alternative Madrid stars rock Barcelona
2 Palermo Sizzling Sicilians sucker-punch Juventus
3 Manchester Utd Keeping title dream alive ... just