Police have detained two Southampton fans who appeared to mock the death of the Cardiff striker Emiliano Sala, on a day when unrelated incidents put fan disorder back in the spotlight.

At St Mary’s, two men were filmed apparently making plane gestures during Southampton’s defeat to Cardiff in reference to the crash which killed Sala and left the light aircraft’s pilot, David Ibbotson, missing.

Southampton later confirmed police had detained two men, adding: “Such behaviour has no place in our game and will not be tolerated at St Mary’s. The club will ban those supporters identified.”

Meanwhile, two men were taken to hospital to be treated for facial injuries sustained during violence outside Vicarage Road following Watford’s win over Everton.

Police said four men were arrested in connection with the incident, which occurred just after 5pm on a stretch of road where the visiting fans’ coaches were parked up.

One witness reported seeing a Watford fan “lying on the floor, apparently unconscious, with blood on his face … Friends around him were crying and shouting for people to help and call an ambulance.”

It comes a month after the Metropolitan police described fighting that broke out before Everton’s FA Cup match at Millwall as “some of the most shocking football violence seen for some time”. A 27-year-old was arrested last week in connection with that incident, which left one Everton fan with “a life-changing” scar having been slashed across the face.