During the New Year period, the Blues have been heavily linked with the Argentina international, who has just helped his country win the World Cup by starring in the centre of the pitch.
Since then, the Young Player of the Tournament has attracted interest from numerous high-profile clubs, despite the 21-year-old only having been at the Estadio da Luz for five months.
However, with Benfica insisting on Fernandez's £106m release clause being met in full, only Chelsea have persisted with trying to negotiate a deal.
At one point this week, it was claimed that Benfica president Rui Costa had decided that the only resolution was to cash in on the former River Plate man.
That was when it appeared apparent that Chelsea were ready to pay over Fernandez's release clause in three yearly instalments in order to wrap up a deal.
Over the past 24 hours, however, reports have emerged which suggest that Benfica are insisting on £106m in one payment or no deal will materialise.
According to Record, Chelsea responded by expressing a willingness to part with £87m as well as three players, one of which is yet to be confirmed as one of their own.
The Blues hierarchy are allegedly prepared to allow Vasco da Gama youngster Andrey Santos to move immediately on loan to Portugal if it boosts their chances of signing Fernandez.
Nevertheless, Benfica are said to have little interest in that proposal, one which is also said to include Hakim Ziyech and David Datro Fofana, the latter also on loan.
Despite impressing for Morocco at the World Cup, Ziyech is only regarded as a squad member by Graham Potter and the playmaker may depart Stamford Bridge before the end of January.
Meanwhile, Fofana has only just signed for Chelsea from Molde, Potter stating at a press conference on Wednesday that no decision had been made regarding the Ivory Coast international's short-term future.
The West Londoners must now decide whether to return with another bid for Fernandez or consider meeting Benfica's demands, aware that the player could attract wider interest in the summer.
Fernandez is already said to have informed Benfica that he wishes to move to Chelsea before the end of the month.