MANCHESTER UNITED have failed in a second bid of £91million for Napoli centre-back Kalidou Koulibaly, according to reports.
Corriere dello Sport claim the Italian club "immediately" rejected the world-record offer.
Getty Images – Getty4 Manchester United have failed in a £91m bid for Kalidou Koulibaly
Jose Mourinho's desperate search for a quality defender saw United up their initial £77m offer by £14m.
The Old Trafford boss was furious at the club's failure to sign a new defender in the summer after botched moves for Harry Maguire and Toby Alderweireld.
In September, he claimed his defenders were not good enough to compete for the Premier League title.
Chris Smalling and Victor Lindelof have become Mourinho's first-choice partnership of late but Mourinho is eyeing a number of targets to improve his back line.
EPA4 Napoli 'immediately' rejected Manchester United's world-record bid for Kalidou Koulibaly
Getty – Contributor4 Kalidou Koulibaly is a Senegal international who Napoli signed for £7m in 2014
Koulibaly, 27, is one of just two players in Europe to have played every minute of football so far this season.
Napoli have conceded just 13 Serie A goals with the Senegal international in the team this season – the fourth best record in the league.
And club president Aurelio De Laurentiis' refusal to sell a player bought for just £7m from Genk in 2014 for a staggering £84m profit highlights how important he is to the side.
Chelsea, Liverpool and Real Madrid have all previously been linked with a move for Koulibaly.
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Mourinho will be hoping to sign Koulibaly as part of an incredible defensive overhaul to raise money for new recruits.
Eric Bailly is set for talks over his Manchester United future — just two years after his £30million switch from Villarreal.
Reuters4 Victor Lindelof and Chris Smalling have become Manchester United's defensive partnership
The Ivory Coast ace, 24, has not started a game since boss Jose Mourinho subbed him before half-time against Newcastle last month.
Smalling is another centre-back on the verge of leaving, with SunSport exclusively revealing strong interest from Everton.
He is available on a free transfer next summer and looks set to be cut loose in order to free up room for new faces.
Meanwhile, Marcos Rojo is reportedly closing in on a move to Premier League new boys Wolves, while Matteo Darmian could be on his way to Roma.