MARTIN O'Neill returns to Villa Park this afternoon for the first time since controversially quitting as Aston Villa boss last August, and the Sunderland manager readily admits his four years at the club “turned sour”.

O'Neill enjoyed considerable success with Villa, finishing in sixth position for three seasons in a row and leading the club to the Carling Cup final, which they lost to Manchester United.

However, his reign ended abruptly as he stepped down less than a week before the start of the season amid mounting rumours of a breakdown in his relationship with Villa's American owner, Randy Lerner.

Lerner later released a statement claiming he and O'Neill “no longer shared a common view as to how to move forward”, but the Sunderland boss has subsequently denied suggestions he was unhappy with a lack of support in the transfer market.

He made a point of not elaborating yesterday, no doubt keen to dampen down the simmering tensions that are expected to see him receive a rough ride from the Villa supporters this afternoon.

But he was willing to concede he had not left the West Midlands on the best of terms and admit to feeling a degree of unhappiness at the way his time at Villa Park came to an end.

“I had the privilege of managing one of the great clubs of English football,” said O'Neill. “They are one of only four English teams to win the European Cup and have a great tradition and history behind them.

“I was there for four years, and I have to admit that in the fourth year, things turned a little bit sour unfortunately. Ironically, that was also our best year because we finished in the top six, got to the final of the League Cup and semi-final of the FA Cup, and were only six points off qualifying for the Champions League.

“That can't be helped, some times these things happen. I'm not in a position here at this moment to change people's minds. Maybe at some stage or another there will be a clearing up of reasons for departure and such things like that, but I don't believe that the eve of this particular game is the right time to do that. I don't think an explanation at this stage would be right.”

O'Neill made similar statements during his introductory press conference as Sunderland manager, and there is clearly a festering resentment about the way in which his departure from Villa Park has been portrayed.

Within the Midlands, he was presented as the villain of the piece, walking away on the cusp of a new campaign and effectively scuppering Aston Villa's meticulous pre-season preparations.

The club's performance since has hardly calmed his critics, with Villa never really recovering from their chaotic start, although some supporters are viewing Alex McLeish's struggles as proof of the extent of O'Neill's achievements during his time at their club.

After finishing 11th in his first season, the Northern Irishman spent three successive years in the top six, a considerable feat for any club outside the established big four, a grouping that has now effectively become a big six with the development of Manchester City and Tottenham.

It is certainly hard to imagine Sunderland becoming permanent fixtures in the top six, but as he seeks to elevate his side from ninth position in the four matches that remain, O'Neill insists they are capable of emulating Villa's achievements.

“Could Sunderland achieve what we achieved at Villa? Of course,” he said. “The club is certainly big enough to have those sort of demands put on it.

“Whether we're able to do it or not is another thing, but that should be the aim of this football club. Clubs like Villa, Everton and ourselves all want to be part of this league and feel that we can do something in it. That's our aim, our mission. Although whether we can achieve it or not is something else.”

For the time being, O'Neill will content himself with putting one over on both his former employers and his successor at Villa Park, Alex McLeish, who is an old adversary from the pair's time on opposite sides of Glasgow's Old Firm divide.

“I admire him greatly, although I never went out to dinner with him up in Scotland,” said O'Neill. “I wouldn't have wanted to be seen in any corner of Glasgow eating with the Rangers manager. It would have been the last time I'd eaten myself.”