Jose Mourinho has challenged teenage midfielder John Obi Mikel to prove he has shed an unwanted bad-boy image.
The Nigerian started his first Champions League match for Chelsea against Werder Bremen last night, as the Blues qualified for the knockout stages despite losing to Per Mertesacker's 27th-minute header.
Mikel was sent off against Reading in the Barclays Premiership in October but Mourinho was more concerned by his poor timekeeping and life off the field.
The Chelsea boss axed the 19-year-old from his squad for over a month but the teenager responded with a full apology and a promise to mend his ways.
Mikel was welcomed back into the Chelsea `family' for the Premiership victory over West Ham last weekend before being handed a place in the side against Bremen last night.
Mourinho said: 'At least he is never late now. I think he has realised what he has to do.
'But my doubt now is if he realises that for the next month or for the rest of his career.
'That's my doubt. I have to wait and see. But at this moment, his reaction has been positive.
'He is training well and hard. He is arriving on time and trains - he is not walking on the pitch. Some players train, others walk on the pitch.
'He trains as well now. He played well in the last game against West Ham when he came on. He had a very positive experience against Bremen because it was a high level game.
'I think he is going in the right direction. Now he's got to stay doing that because when he does so I want to help him.
'I want to help him in his career because he has a lot of potential. But now we have to wait a little bit to see if it is a permanent change or just a change because he was punished.
'He was out of the team for a month but has now been involved in consecutive matches.
'You have to give players chances in relation to what they do on the pitch and if they are not trying or not performing or behaving, they have to feel it.
'The best way to feel it is for them to sit on the bench, in the stands or at home.'
Mikel was impressive until he was substituted in the second half as Chelsea chased the point which would have seen them win Group A.
They must now beat Levski Sofia at home to clinch top spot, although Mourinho has more immediate concerns ahead of Saturday's match against Manchester United.
Striker Didier Drogba and midfielder Michael Ballack were both injured against Bremen.
Mourinho said: 'Ballack's injury is nothing special. It is just pain.
'The opposing player put his studs on his muscle and it is just painful.
'Didier is the same. He has a pain in the ankle but it is nothing serious. Normally, he will be fit enough for Sunday.'
Chelsea had chances against the Bundesliga side but Bremen goalkeeper Tim Wiese saved superbly to deny both Ballack and substitute Andriy Shevchenko.
Even though they stumbled to their first defeat in the competition this season, Mourinho was happy with qualification.
He added: 'I am never happy with a defeat but this is different because we have still qualified for the second stage of the competition.
'But to go into the last game of the group stage having already qualified is an achievement. That is very important.'