Manchester United have made an improved £43million bid for Ajax defender Lisandro Martinez but the Dutch side are yet to accept the offer.
Ajax are waiting to see if Arsenal make a rival bid as they look to stir up an auction between the Premier League sides.
The new offer is £5million more than United's last proposal and is thought to be close to Ajax's valuation — with the Dutch side mindful that the 24-year-old is desperate for a move to England.
Martinez - who has earned seven caps for Argentina - remains open to joining Arsenal if they meet Ajax's valuation.