Southampton boss Ronald Koeman was disappointed with their performance in defeat to Sunderland.

Koeman didn't feel his side really played until they went down to ten after James Ward-Prowse's dismissal.

"Yes, that's true (Saints were flat)," said Koeman. "I think we didn't reach our level. Frustrated about that.

"It's strange that with one player less on the pitch we showed our football and our qualities and before not.

"I think we had too much mistakes in our ball possession.

"The first ten minutes after half time was very poor and out of one of those situations came the penalty, the red card, and then you know it's difficult.

"That's so strange and sometimes understandable that the reaction then is with one player less that we were the better team and the dominating team and that's difficult to understand."