Manchester United are set to make an improved bid for Robin van Persie after making a breakthrough in talks with Arsenal on Tuesday night.Arsenal want at least £20 million for their captain but United have until now been reluctant to offer more than £15m for a player who is 29 and has just one year remaining on his contract.The new offer is likely to be close to Arsenal’s asking price once add-ons are included as the two clubs attempt to reach an agreement and draw a conclusion to the summer saga.United are firmly in pole position to sign Van Persie and could even complete a move for the Dutch striker before their Premier League opener against Everton next Monday.Goal.com revealed last week that the demand of Van Persie's agent, Kees Vos, for a £4m cut in the deal has threatened to scupper his chances of a move to Old Trafford.Manchester City had previously been favourites to land last season's double player of the year but have put their interest on hold due to the finances involved and their difficulty in selling Emmanuel Adebayor, Edin Dzeko and Roque Santa Cruz.Juventus are also out of the running for the former Feyenoord man, leaving United with a clear run despite Arsenal's reluctance to sell their star player to a Premier League rival.The Gunners, however, appear to have concluded that they would rather sell Van Persie than keep an unhappy player in the squad who can leave on a free transfer next summer.Van Persie, who is currently in Belgium on international duty with the Netherlands squad, has publicly announced that he will not sign a new Arsenal contract.Sir Alex Ferguson was unsure when asked last week about United’s chances of landing the man who was the Premier League's top scorer last term with 30 goals."We have made a bid and they've [Arsenal] been trying to negotiate with other clubs," said Ferguson. "I don't have a gut feeling on it at the moment, I must admit."We're not getting any breakthrough with Arsenal. It's difficult to say why they're operating this way. I don't know what their thoughts are, because they're not giving anything away."But Van Persie now looks likely to complete a switch to Old Trafford where he will join new signings Nick Powell, Shinji Kagawa and Angelo Henriquez, who will complete a £4m move to the club after undergoing a medical.