Southampton’s automatic promotion hopes hang by a thread after a crushing 2-1 defeat in the Welsh capital on Saturday. Cardiff were the 2-1 victors in a game that Southampton really should have put to bed within the first half. All was going to plan as Joe Aribo continued his recent form, sweping home a left-footed strike following a goalkeeper parry from an Adam Armstrong effort on 12 minutes. Russell Martin watched on as his side cut through their opponents at will in the first 45 minutes and it looked for all the world that the Saints were going to secure their fourth consecutive win. South…