Martin O'Neill insists Aston Villa have to fire on all cylinders in every game to achieve success ahead of the Carling Cup clash with Sunderland at the Stadium Of Light on Tuesday night.

O'Neill is pleased with Villa's overall start to the campaign after the shock of losing at home to Wigan on the opening day.

But the former Celtic boss believes Villa are "not that good" to be able to win matches when not at their best.

This has been highlighted with Villa collecting seven points from the meetings with Chelsea, Liverpool and Manchester City but only one from games with Wigan, Blackburn and Wolves.

He said: "I don't think we should get too carried away by it all. We only have to look back to the opening day of the season against Wigan when disaster abounded.

"We fought back and overall we have continued reasonably well since that. It has been a fine start and the games versus Manchester City and Chelsea gave us confidence.

"After the defeat against Wigan, I had to deflect a lot of questions and there was a rush to judge.

"As a consequence, I don't think there is any point in us getting carried away with a reasonable start to the season."

O'Neill added: "Overall the performances have been fine. We have tried to recover from the loss of the players like Martin Laursen and Gareth Barry and it has been coming along nicely, but that's all.

"Despite the fact we played brilliantly against Man City and Chelsea, we are not that good that we are capable of dismissing any opposition.

"We are incapable of doing it. We haven't reached that stage at all. We are getting a decent mentality about ourselves without getting carried away."

Villa have had a poor record in knockout competitions, losing to a succession of lower ranked teams in recent years, and it is 13 years since they won their last major trophy, the League Cup in 1996.

O'Neill said: "I know during the last couple of years we have got knocked out early on which has been a big disappointment.

"Last season we were still heavily involved in the European scene and maybe the disappointment might not have lasted that long.

"But we don't have European football to go for and I would dearly love to do well in the competition if it is at all possible. The football club would be very keen to progress in it."

O'Neill may decide to make changes against the Black Cats but is adamant that will not mean fielding a weakened side.

He said: "I said I was going to try and utilise the squad this year but the players who will come in are not peripheral players. They are players who, in the case of one or two, perhaps might consider themselves unlucky not to be in the starting line-up.

"From that viewpoint, whatever side that goes out I would be happy in the knowledge that we will be capable of winning the game."

Emile Heskey, Luke Young, Habib Beye, Nicky Shorey, Nigel Reo-Coker, Fabian Delph, Brad Guzan and Craig Gardner could all be in contention to start.

England striker Heskey in particular would be keen to make an impression after having to play second fiddle to Gabriel Agbonlahor and John Carew for much of the season.