Borussia Dortmund are showing an 'increasingly strong' interest in Benfica midfielder Nemanja Matic, according to Portuguese newspaper A Bola.
The Serbian midfielder has been attracting interest from a host of European clubs in recent months following some sterling performances in Portugal.
Chelsea have been heavily linked with a move for the 25-year-old, with boss Jose Mourinho admitted he was impressed with the midfielder's recent performances.
Matic actually joined Chelsea in 2009 from Košice for €1.9 million - but was allowed to leave Stamford Bridge as part of the deal that saw David Luiz arrive in west London.
According to A Bola, the Blues will face serious competition from Borussia Dortmund in the race to land Matic.
The paper claims that Dortmund boss Jurgen Klopp views the Serbian international as the ideal addition to his midfield, with Ilkay Gundogan injured and being linked with a move away.
Benfica are reluctant to sell but may be forced to in order to balance the books.
According to A Bola, a bid from either Chelsea or Dortmund in the region of €30 million - well short of the €50 million release clause in his contract - will be enough to convince the Portuguese club to sell up.