Aston Villa manager Martin O'Neill insisted the buck stopped with him after his side's 1-0 defeat at the hands of relegation battling Sunderland.

The Northern Irishman could give no answers as to his team's poor performance which left them failing to score on home soil in the league for the first time this season.

For Sunderland boss Roy Keane, it was their first away win of the campaign and it dented Birmingham City's hopes of survival in the Premier League.

O'Neill refused to use the lack of options in his squad as an excuse, despite the fact that he possesses the fewest first-team players of any team in the Premier League and has no option to rotate players, or rest those who are not performing at the top of their game.

He said: "We were very disappointed to lose that game. I thought we set out boldly enough but then we had one or two missed passes and the keeper [Scott Carson] started getting a bit anxious.

"We had one or two chances but didn't take them and then Sunderland started putting the pressure on. Suddenly, from trying to win the game, we actually lost it."

Michael Chopra, who had been dropped from Keane's matchday 16 for the match against Chelsea the previous week, had not scored in open play since Sunderland drew 2-2 with Birmingham City at St Andrew's in the second match of the season.

Yet he struck in the 83rd minute on Saturday and O'Neill said: "It was really disappointing to concede that goal. This was a home game and it was our responsibility to win the game and make it as entertaining as we could."

O'Neill said nerves might have played a part but admitted his side should still have been able to calm themselves and take something from the match, which was played before a capacity crowd of 42,000.

He said: "We went out there knowing Portsmouth had been beaten and we should have done better. Since our 1-1 draw with Arsenal last month we have been really disappointing and, having just had two home games, we would have expected better than one point from six [they drew 1-1 with Middlesbrough 12 days ago].

"From the confidence that exuded from the team at that time, you would not have expected this but it is my responsibility and I have to rectify it."

O'Neill's biggest disappointment was letting down the bumper crowd - many of whom had already left when the final whistle blew, after seeing their side's below-par performance. He said: "The fans had come out in big numbers to support us and we should have done better for them but that is my responsibility.

"Our performances in the last three games have shown we have got miles to go but we have got to keep going. This was one of those games where, regardless of performance, winning was the all-important thing.

"I felt that if we had scored the first goal, we would have gone on to win it. I didn't really see us losing the game and we lost it in very disappointing circumstances.

"The biggest thing of all is learning to win even when we are not playing well. The really good teams win when they play badly and I think the crowd would have forgiven us that if we had eked out a win.

"It's my job to get things right. We had over 42,000 people at the game and they were expecting better than that. Every misplaced pass is my job. I've got to look at it and I have to do better.

"However the team performs, it's down to me. If there's plaudits to be had I'll take them, but I do take it personally when we lose.

"I have been here for 18-19 months and this is as low a point as I've felt. This defeat shows that we have a good distance to go. Maybe it's been a bit of a check for all of us. I expect better."