A smattering of boos as the final whistle blows. Mourinho shakes Koeman’s hand sadly, then slopes off down the tunnel. The champions are in all sorts of trouble right now. Only West Brom, Villa, Newcastle and Sunderland are beneath them in the Premier League table. John Terry walks off with his head in his hands. But this isn’t just about crisis-club Chelsea; it’s about Southampton too. And they were simply magnificent.