Chelsea are 19 points behind Premier League leaders Manchester United and they crashed out of the UEFA Champions League in the group stages.
Most of the season has been played to the soundtrack of angry supporters chanting reminders to interim boss Rafael Benitez that he is not welcome at Stamford Bridge.
Brazil international Luiz recognises Chelsea have been poor but he is determined the club can rescue their season by lifting the UEFA Europa League crown and the FA Cup.
"I think we are not playing at the level expected from Chelsea and not doing so well this season but in any case I believe we are because we are still competing for three titles," he said.
"We can still win the Europa League, are still in the FA Cup and fighting for a better position in the table so I think we can still get there and this season can still be very good."
Luiz will be in a familiar surroundings on Monday night when he plays for Brazil against Fabio Capello's Russia in a friendly at Stamford Bridge.
It will be a special moment for the defender and a special moment for the Brazil manager Luiz Felipe Scolari, who spent seven months in the Chelsea hot-seat during the 2008-09 season.
Chelsea were fourth in the Premier League and still in both the FA Cup and Champions League when Scolari was sacked in February 2009, with Russian owner Roman Abramovich saying the decision was made so the club could "maintain a challenge for the trophies we are still competing for".
Luiz believes the manager could have a point to prove at Stamford Bridge on Monday, adding: "Mr Scolari is an excellent professional. He has been a coach in many clubs all over the world and also national teams.
"I'm sure he is happy to come back here because regardless of what happened here he has very good memories.
"He has got history here as well so I believe what he wants here is to put the cherry on the top of the cake by winning the game at the stadium where he was manager."
Luiz's Chelsea team-mate Oscar could also be in action for Brazil on Monday night and hopes his experience playing in different positions for the Blues will help him against Russia.
"I like to play in all positions, I'm used to playing in different positions at Chelsea," Oscar, who scored in the 2-2 draw with Italy last week, told Terra. "That helps me a lot. It can't be any different for the national team.
"Let's see what Scolari will decide for this match. Hulk and I swapped places a lot [against Italy] which is good to mislead the opponent. I hope it works against Russia too."
Ramires is a Chelsea player who will not be involved against Russia after the Brazilian Football Association confirmed he has withdrawn from the squad, having missed the Italy game with a thigh injury.