As Chelsea's problems deepen, Jose Mourinho will attempt to revive his side's disastrous campaign by masterminding a victory against Southampton at Stamford Bridge today. Another testing week has only added to the growing sense of unease around the club, with Mourinho forced to defend his relationship with his players after making unexpected changes for the Champions League trip to Porto. The Blues boss reacted to last weekend's English Premier League draw at Newcastle - Chelsea recovered after falling two goals down to Steve McClaren's struggling team - by leaving Oscar, Loic Remy and Radamel Falcao at home in midweek and starting Eden Hazard, John Terry and Nemanja Matic on the bench. They didn't concede a lot of goals but this season it's different. Maybe for that the confidence is not the same Ronald Koeman The overhaul did not have the desired effectthe manager had hoped, with Chelsea slumping to a 2-1 defeat that reinforced the view that Mourinho's side this season are a shadow of the team that eased their way to the Premier League title in May. The visit of Southampton will provide another stern test, with Saints manager Ronald Koeman voicing his confidence that his side can get something from the game after twice holding Chelsea last season. Mourinho's men need a lift and injured keeper Thibaut Courtois expressed the frustration currently gripping the club. The Belgium goalkeeper, now sidelined with a knee problem, said: "It is not easy, no, to see all that, and not be part of the team at the moment, and being unable to help. "Tuesday, in the Champions League, they lost, playing a good game. But we will progress. And Saturday, we have to win at home. There is pressure, and I hope we will win. After that, there is the international break, and then I hope Chelsea win a series of matches. "We have tough matches, but we must do better than now." Chelsea's success last season was built on their defensive strength but Courtois' absence, together with Branislav Ivanovic's dramatic loss of form and John Terry's frequent demotion to the bench, means the back four is not what it was. And the keeper does not expect to be fit enough to challenge his deputy for a starting spot for at least another two months. "Hopefully, early December. If there are complications, I will work quietly to return. For now, I cannot give a date," Courtois said. Koeman, meanwhile, is in no doubt about where Chelsea's weakness lies. "Maybe they have some defensive problems. I think if you look back to last season they were the team with our defenders who had the best defensive record," he said. "They didn't concede a lot of goals but this season it's different. Maybe for that the confidence is not the same. They showed their character last year. "If you were looking to the Chelsea team you felt that it was a winning team. Maybe they are struggling a little bit more this season." Koeman, though, does not expect Mourinho's side to remain in the bottom half of the table for long and admits his side will have to perform even better than they did in beating Swansea 3-1 last weekend. "For sure we know it's a difficult opponent. They will look to react after the loss against Porto in the Champions League," he said. "They will go up in the table because they don't stay that low for so long. We know what they can bring. We know their qualities. We have to be good and at a very high level to get a good result. "We know what to expect. We had two good results last year against them, but we have to play at a higher level than we did against Swansea last week."