Goals from Michael Tonge, El-Hadji Diouf and Luciano Becchio’s penalty helped Neil Warnock’s side progress into the quarter-finals, leaving Southampton without a win in five games in all competitions.
“It was a poor result for us,” Adkins told the club’s website.
“It was a very attacking formation on paper, but on the pitch you have got to go and produce it.
“You’re playing for Southampton Football Club, so every game matters. We’ve got supporters who have travelled, and we’ve put a team out that I expected to win this game.
“I expect the players to go and perform, so there’s obviously going to be consequences of the result and performance for many people.
“We’ve come out to win a game of football – on paper and in theory that was possible, but we haven’t produced.”
He added: “I have to take full responsibility for the team that goes out and all it’s done.
“I’ve made changes because we played 48 hours ago, and you can talk about the recovery process all day long – the last thing you want to do is lose players for long periods of time.
“We’ve got to make sure that we address anything that is going wrong in any way we can for the sake of this football club, because that’s what it’s about.”
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