Gelsenkirchen - Chelsea's Jose Mourinho insists hot-shot striker Diego Costa would 'be nothing' without the team around him as the Premier League leaders look to secure their Champions League progress on Tuesday.
Group G leaders Chelsea need a win at Schalke on Tuesday to confirm their place in the Champions League's last 16 having drawn 1-1 against Germany's Royal Blues at Stamford Bridge in September.
Mourinho's opposite number Roberto di Matteo is seven games into his new job as Schalke coach since being sacked by Chelsea in 2012 just six months after winning the Champions League title.
Under Mourinho, Chelsea are unbeaten in all 18 matches this season and are seven-points clear at the top of the Premier League with Spain striker Costa having scored 11 goals since his transfer from Atletico Madrid.
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But Mourinho balked when asked if Costa is the best striker he has ever worked with.
"Without the team he has behind him, Diego is nothing," said Mounrinho, who is bidding to become the first manager to win the Champions League with three different clubs.
"He is scoring goals and playing well, but the team is producing a lot."
Mourinho says players like goalkeeper Thibaut Courtois, who is back from a loan spell at Atletico Madrid, plus Cesc Fabregas from Barcelona and the return of Didier Drogba from Galatasaray have strengthened the team.
"It's not fair to talk about an individual player when the team is playing well behind him, but players like him are improving the team."
"Those like Thibaut and Fabregas, who are also doing well."
Chelsea have set a new club record of 12 league matches unbeaten this season and it is all down purely to hard work, says Mourinho.
"The players are playing very well in every competition, we are getting good results, but nothing has come for free or from luck," said the self-styled 'Special One'.