Amid a defensive crisis at the club, Barcelona defender Marc Bartra has vowed to hold down a place at centre-back in the final weeks of the season. Injuries to Carles Puyol and Javier Mascherano have meant the 22-year-old has started each of Barca's last three league games. And with Adriano suspended for Tuesday's Champions League semi-final first-leg against Bayern Munich, he could well partner Gerard Pique in Germany. "When there are difficult games you try to give your best. I have spent the whole season preparing for when my moment came," he said. "I will try to do my best. Physically I am good and every time I play I feel better." Barca need just three more wins to seal a fourth title in five seasons - even assuming no Real Madrid slip-ups in the coming weeks. Bartra is delighted with how the Catalan club have managed to stay focused in La Liga, having led from the front for most of the season. "It is not easy, even when you are so many points in front. "We haven't relaxed, even when having the Champions League games that we have had. It is not easy to be so many points in front and maintain that distance. The work we have done is something to be proud of," Bartra said. It is not easy to be so many points in front and maintain that distance. The work we have done is something to be proud of Lionel Messi returned to training on Thursday as he continues to recuperate from a hamstring injury, but the Argentinian is not expected to play any part in today's clash with Levante to ensure he is fit for the trip to Munich. Sergio Busquets is also likely to miss out this weekend, as he is still struggling with a pelvic injury, while the talented likes of Xavi, Andres Iniesta, Jordi Alba, Dani Alves and Pique could be rested. However, Levante captain Sergio Ballesteros does not believe Messi's absence will have a major impact on the game. "Barcelona have played some games without Messi and they continue to be Barcelona," he indicated on Wednesday. "In key moments you can depend on your best player, but as a team they don't need him to win games. "If he plays, it will be a confidence boost for them and if he does not, as they showed in Zaragoza, they are capable of beating anyone because they have an extraordinary squad." Real Madrid are also in action today as they take on Champions League-chasing Real Betis at the Santiago Bernabeu. Los Blancos are on Champions League duty themselves in midweek against Borussia Dortmund and after naming a surprisingly strong side for the 3-0 win at Athletic Bilbao last weekend, Jose Mourinho is expected to return to his policy of resting key players ahead of big European games.