Guardiola has a defensive crisis after further Barça injuries

Real Sociedad 2 Barcelona 1

Guardiola is preparing his team to take on United on 28 May (REUTERS)

With Uefa set to ban Jose Mourinho for up to four games for his post-Champions League semi-final first-leg comments he will wonder if life as Real Madrid coach could get any worse. The answer is: yes, it could.

Had Barcelona not fallen to only their second league defeat of the season the gap at the top would be 11 points and not eight as the two teams prepare to go into battle for the fifth and final time this season tomorrow night.

Barcelona's players watched Real Madrid's lacklustre display against Zaragoza on Saturday and then produced one of their own at the Anoeta Stadium in San Sebastian, meaning both sides lost on the same day for the first time since August 2008.

Of more concern to coach Pep Guardiola will be injuries to Gabriel Milito and young left-back Martin Montoya. Centre-back Milito will miss tomorrow's second leg with a thigh strain and Montoya will be out until next season after breaking his collar bone. The youngster is the fourth left-back Guardiola has lost and he admitted afterwards: "We are very low on numbers and need the help of everyone to finish the job. Madrid will arrive with nothing to lose and it is going to be a very hard game in more ways than one."

The two teams will know Uefa's judgement on the Battle of the Bernabeu before they take to the pitch after European football's governing body brought forward its disciplinary meeting's hearing to today. Goalkeeper Jose Pinto will find out if his part in the half-time fracas last week will cost him more than the one match ban he will serve tomorrow. He started this game as Guardiola left Dani Alves, Sergi Busquets and David Villa out of his starting line-up.

With Cristiano Ronaldo watching Real Madrid's defeat from the stands, Leo Messi started. Regardless of whether Ronaldo was being punished for his post-match comments about not liking his team's negative tactics, or just rested, the extra game for Messi gave him a chance to extend his lead over Ronaldo in the goalscoring charts.

The Argentine could not add to his 31 league goals this season but Barcelona did make a good start when Thiago Alcantara netted on the half hour. The goal meant Pep Guardiola's side became the first team ever to score 45 goals away from home in one La Liga season.

Barcelona threatened more goals in the second half but with Real Sociedad desperate for the points to secure top-flight safety and the visitors already playing with the assured cushion of eight points after Madrid's defeat they let the lead slip. Diego Ifran equalized with 19 minutes left and, after Javier Mascherano brought down David Zurutuza, Xabi Prieto gave the home side the lead from the spot in the 82nd minute.

"It's always better to go into a Champions League game off the back of a win," said Guardiola. He, like Mourinho, must now lift his players, although needing just four points from four games to win the league and being 2-0 up ahead of the second leg will make his task easier than his rival's.

Real Sociedad (4-2-3-1): Bravo; Martinez, Demidov, Gonzalez, Estrada; Rivas (Zurutuza, 68), Markel; Xabi Prieto, Aramburu, Griezmann; Tamudo (Ifran, 68).

Booked Tamudo, Estrada.

Barcelona (4-3-3): Pinto; Montoya (Alves, 13), Pique (Mascherano, 62), Milito (Busquets, 77), Fontas; Xavi, Keita, Thiago; Afellay, Messi, Jeffren.

Booked Mascherano.

* Uefa yesterday handed Frank de Bleeckere the task of refereeing Tuesday's Champions League encounter between Barcelona and Real Madrid – an appointment unlikely to go down well with Mourinho. The Real coach last week accused referees of favouring the Catalan side . The Portuguese was enraged by the dismissal of makeshift midfielder Pepe by Wolfgang Stark and afterwards read out a list of officials he believes have made decisions which have benefited Barça in previous years. De Bleeckere was on that list after opting to send off Thiago Motta in last season's last-four game between Internazionale, then managed by Mourinho, and Barça.