Arsenal have been told to up their record offer for Valencia star Juan Mata.
The Sun says the Gunners were lining up an £18m bid with boss Arsene Wenger seemingly ready to embark on his much-talked about summer spending spree.
But the Spanish outfit will hold firm for their most prized asset who signed a new four-year deal in January.
A top Valencia source said: "There are specific clauses in Mata's contract and, unless a club is prepared to match those, there is no chance Mata would leave. The club do not want to sell the player."
Mata can leave for £23 million.
