Chelsea manager Jose Mourinho praised Diego Costa and believes only confidence is missing in the striker's game.
Costa's struggle for goals continued as Mourinho's men reached the last 16 in the Champions League with a 2-0 win over Porto on Wednesday.
The Spain international was involved in a row with the manager in November and has scored just four goals in all competitions this season.
Mourinho was happy with Costa's performance against Porto and said the 27-year-old was just lacking confidence.
"It's clear but what is also clear is his effort, commitment and great movement, which is something he hasn't had in the last couple of months. Tonight it was great," he said.
"The first goal was obviously an own goal but his movement was great when the pass arrived. Last season he would have scored immediately but this season he couldn't.
"With the second chance when he faced the keeper on his own, you could immediately feel the lack of confidence because the first thing he did was not attack the goal but look to the linesman. When he did that he lost an important second and his last touch on the ball was not the best.
"He could have scored two or three goals today. There is a lack of confidence, clearly, but his attitude was very good and his movement was much better, so goals are coming.
"I took him off not because I was unhappy with his performance but to give something different to the team, to attack the spaces with faster people."
Mourinho maintains belief in Chelsea's chances of finishing in the Premier League's top four, despite being 14 points behind Manchester United.
The Portuguese tactician said he would continue believing in his team.
"The Premier League boss said in an interview it would be good for the league if Chelsea were not champions," Mourinho said.
"But he didn't say it's not good for the Premier League if Chelsea finish fourth, so while mathematically it's still possible let’s fight for every game and every point and see if it’s possible to finish fourth."
