Swansea City interim manager Alan Sheehan admits his team’s humiliation at Southampton on Boxing Day was “unacceptable” and insists he understands fans’ frustration as the search for a permanent manager drags on.

Skipping the last four games, Sheehan found himself back on the Hampshire bench watching Russell Martin’s Saints mercilessly destroy his team.

The manner of this defeat was particularly disastrous. Not just for Sheehan’s long-term job prospects, but also for ownership, who once again found themselves in the spotlight due to Martin’s pre-game comments.

“We came here with the intention of playing one of the best teams in the league,” Sheehan said after the game.

“We wanted to be brave and be at the front. For much of the first half we were in great shape in the game. The second goal kills us. Individual mistakes happen. Then the third goal was the same.

“I didn’t like the second part. We had honest conversations. This is unacceptable. Every now and then we scored goals for them and made things very difficult for ourselves.

“I thought when we played our game in the first half we were good. I think we played well. Then, in the second half, conceding the second goal so easily is a real bummer.

“It is unacceptable, but I take full responsibility.”

Meanwhile, there is bad news for full-back Josh Key, who was left out of the squad for the game at St Mary’s after scoring in Friday’s win over Preston North End. Sheehan has since revealed that the 24-year-old has suffered a hamstring injury and could now be sidelined.

“It’s disappointing,” Sheehan said. “He’s seeing a physical therapist. He has had a scan and is about to have a second scan. “He’s going to be out for a while, which is very disappointing because we’re in a place where Josh Key is giving us something that we don’t have a lot of right now.”

It appears highly unlikely that Key will feature in Friday’s trip to Coventry City, and it remains to be seen whether Sheehan himself will be on the bench.

Swansea’s search for a new manager appears no closer to a foregone conclusion and it is understood Sheehan is likely to take charge for the clash with the Sky Blues.

“I can’t give you an update,” he said when asked about the latest developments. “I’ll talk to the owners and everyone after today’s game. Now we have to recap this game. We are very, very disappointed. This is my first game of this type.

Asked if he expected to remain on the bench on Friday night, he added: “I’m looking forward to the negotiations.

“I understand everyone wants clarity. Now all I can do is prepare the team for each game they ask me to play. We did very well in four games. We played four games and in the first half today I thought: where are we? So that’s a really disappointing half.

“I understand the frustration. I can’t ask any fan to do anything. I just walked in and they asked me to do a job and I tried to do the best I could. No, we don’t actually have Christmas off, but that’s the way it is. This is how we want it to be. But getting this performance in the second half is disappointing. We have to look at it, understand why it happened and make sure it never happens again.

“I think it’s important that we all get answers soon, and I’m sure we will.”