Chelsea manager Jose Mourinho has admitted that Diego Costa is low on confidence in front of goal right now, but believes that his striker will have benefited from playing 90 minutes of the midweek victory over Sporting Lisbon.

The 26-year-old has failed to find the net in his last four outings for the Blues since scoring his 11th Premier League goal of the season against West Bromwich Albion last month.

Despite this, Mourinho believes that Costa showed signs that he is returning to his best in the 3-1 victory over Sporting in the Champions League on Wednesday night, and is happy with the progress shown by his summer signing.

"He wants to improve his condition," Goal.com quotes the Portuguese as saying. "The confidence is not high, the condition is not the best but he wants to use the game [against Sporting] to chase lots of runs and movements, always wanting the ball, always wanting to associate with the wingers and with [Cesc] Fabregas.

"[It was] very important for him. I saw him better than against Newcastle, better than against Sunderland. This game was important for him."

Costa made the move to Stamford Bridge from Atletico Madrid in the summer for a fee of £32m.