Manchester United have reportedly identified Napoli centre-back Kalidou Koulibaly as their number one transfer target when the window reopens this summer.

The 28-year-old has regularly been linked with a move to Old Trafford in recent years, but they instead moved for Harry Maguire last summer as they made the England international the most expensive defender of all time.

United splashed the cash again in January while landing top target Bruno Fernandes, and The Mirror reports that they have now earmarked Koulibaly as their next big signing.

The club's hierarchy are understood to view Koulibaly as the perfect centre-back partner for Maguire, who has already been named United's captain despite only joining last summer.

Koulibaly is likely to cost United another world-record sum, with outspoken Napoli president Aurelio De Laurentiis expected to demand at least £90m for his services.

The Red Devils are willing to meet that asking price and make the 28-year-old the highest-paid player at the club, although their chances of enticing him to Old Trafford could depend on whether they qualify for the Champions League or not.

Real Madrid, Paris Saint-Germain and Chelsea are among the other clubs also thought to be interested in Koulibaly, and the prospect of Champions League football could give them the edge over United.

Nevertheless, Ole Gunnar Solskjaer's side will reportedly step up their pursuit of the Senegal international ahead of the summer transfer window.