Chelsea are reportedly locked in talks with Benfica to sign Brazilian defender David Luiz.
The 23-year-old international has emerged as Carlo Ancelotti's number one target to bolster his defence.
It is understood that Benfica shunned an offer of €25million plus Paulo Ferreira at the weekend.
But now Chelsea are said to be thinking about upping their offer to €30million (£25million).
Benfica are keen to keep Luiz until the summer, but local sources say they will do business if Chelsea come up to the £25million mark.
Chelsea, who missed out on the signing of Steven Pienaar earlier this week, will be anxious to make some sort of breakthrough in the transfer window in order to bolster their faltering title bid.
They have also been strongly linked with Atletico Madrid's Diego Godin and Neven Subotic of Borussia Dortmund.