Manchester United are concerned that failure to qualify for the Champions League will put rivals City top of the queue for one of their main summer targets.
The city rivals have both been linked with a move for Monaco left-back Benjamin Mendy this summer.
The Manchester duo are both keen on bringing in a new left-back this summer and the 22-year-old has been pinpointed as a top target.
City want to add a youthful look to their backline, with current first-choice left full-back Aleksandar Kolarov turning 32 this year, while back-up Gael Clichy is out of contract at the end of the season.
United have pinpointed their left-hand side of defence as a problem area, with Daley Blind, Marcos Rojo, Matteo Darmian and Ashley Young all playing in that position this season, while Luke Shaw’s future at the club continues to remain in doubt.
And the Daily Star report that the defender will be tempted away from the Ligue 1 outfit by a team offering him continued Champions League action.
And Manchester City currently sit one place above United in fourth spot, with just six games remaining.
Jose Mourinho’s men reduced the gap between the two teams to one point after Sunday’s 2-0 win over Burnley at Turf Moor, thanks to first-half goals by Anthony Martial and Wayne Rooney.
The Red Devils could also secure Champions League qualification by winning the Europa League.
United will face Spain’s Celta Vigo in the semi-finals of the competition after dispatching Belgium side Anderlecht in a tense quarter-final last Thursday.
Mendy is currently worth £30million, however, the report claims Monaco could demand double that fee.