Real Madrid are considering raising their offer for Kylian Mbappe to £171.6m (€200m).
The Spanish club have already made a bid of £145.8m (€170m) plus £8.57m (€10m) in add-ons and are waiting for a response from PSG by 5pm UK time on Monday.
Anything past that and it will become more and more difficult for a deal to be done, especially because Mbappe is due to be with the France squad at Clairefontaine.
Madrid are considering raising their offer to £154.4m (€180m), or £145.8m (€170m) plus £25.7m (€30m) in add ons.
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Mbappe scored twice for PSG on Sunday evening as they won 2-0 at Reims. He said on social media after the game it was "the perfect night".
The 22-year-old is out of contract at PSG in 10 months and believes he has been promised he can leave if any club matches the €180m (£154.33m) PSG paid Monaco for him in 2017.
Mbappe has told PSG that if they do not sell him now he will move to Madrid as a free agent next summer.
PSG sporting director Leonardo said last week Mbappe wanted to leave but they would not sell him in the final week of the window and they would not sell him for less than his market value.
Madrid are determined to sign Mbappe, and if PSG refuse to let him leave before Tuesday's deadline, they will try to sign him on a pre-contract agreement in January so he can move to Spain as a free agent next summer.
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