Cesar Azpilicueta confident of collective improvement at Chelsea following defeat to Basel With nine games next month, December is a time when Chelsea can show their Barclays Premier League title credentials as they bid to win the championship for the first time since 2010. Jose Mourinho has described the period as "only for the braves" and is planning to make regular changes to his side to cope with the congestion. Spain right-back Azpilicueta, who has been deployed at left-back in recent weeks, believes every member of the Chelsea squad can play their part. "We have nine games in December and that's a lot," Azpilicueta said. We need the whole squad, there are a lot of games and if we are to win trophies, we need everyone. The most important thing is the next game against Southampton, especially after beating West Ham we need to get three points at home. Sunday's Southampton contest carries additional significance as Mourinho will demand a response from the lacklustre loss at Basle, when Chelsea failed to muster a meaningful shot on goal just a few days after a dominant display at West Ham. "Sometimes it happens," Azpilicueta added. One day you play really well, three days later really bad. We don't want to have this kind of movement in our performance because it's important to keep your balance, to play well every day. Sometimes you cannot play very well but the most important thing is to win. Sometimes we don't keep the level to win every game. For Chelsea that cannot be possible. Sometimes you can lose for sure, but I think we can play better and have better games. Mourinho was scathing after the 2-0 loss at Newcastle early in November, but refused to criticise his "tired" players following a second defeat to Basle in Champions League Group E. Despite the loss the Blues advanced to the last 16, although they must beat Steaua Bucharest on December 11 to go through as group winners. Azpilicueta was apologetic to the supporters who made the trip to Switzerland. He said: "We didn't want to do this. We tried to do our best and it's true they came from London and a lot of countries to be here and we didn't have our best game. The only thing I can say is that for the next game we will try to do better and score goals. Azpilicueta believes the mental fatigue must be as carefully managed as the physical tiredness. "It's normal when you play every three days that the players feel a little more tired," he added. The most important thing is the mental approach, to forget the tiredness of the body. Azpilicueta has impressed since being drafted in at left-back, playing on his 'wrong' flank, in part due to Ashley Cole's niggling rib problem. The Spaniard said: "The most important thing is to think about the team. The manager asked me to play there so I try to do my best. Everyone in the squad wants to play and help the team.