Juan Mata says 'mental strength' the key after Chelsea loss

Chelsea’s N’Golo Kante scores their fourth goal in the match against Manchester United at Stamford Bridge, London October 23, 2016. — Reuters pic

Manchester United's Juan Mata believes remaining "mentally strong" will be vital to their hopes of bouncing back against Manchester City in Wednesday's derby clash following a thumping defeat by Chelsea.

Sunday saw United's six-game unbeaten run in all competitions come to a spectacular end as Chelsea won 4-0 in the Premier League at Stamford Bridge.