Portsmouth boss Harry Redknapp has admitted defeat in his pursuit of Stilian Petrov after revealing the Celtic midfielder is heading for Aston Villa.

Villa and Pompey have both been interested in signing the Bulgaria international who is rated in the £7 million bracket by The Bhoys.

But Redknapp told BBC Radio Five Live: "I think you will find Petrov has gone to Aston Villa. That is the plan and we wish him all the best."

Petrov has been O'Neill's number one target since he came to Villa although he has been reluctant to make any comment about any potential transfer dealings.

The possibility of him arriving at Villa would appear to have increased if reports indicating Celtic are about to sign Thomas Gravesen from Real Madrid for £2 million prove accurate.

However, Petrov's agent insists no deal is imminent with the 27-year-old away with the Bulgaria squad preparing for the Euro 2008 qualifiers against Romania and Slovenia.

But Tony McGill admits the situation could change quickly ahead of the transfer window closing on Thursday night.

McGill said: "It would be pretty difficult for him to be on his way to Villa because he is away with Bulgaria.

Petrov joined the Hoops in July 1999 for £2 million from CSKA Sofia, but struggled to make an impact under then head coach John Barnes following his move.

However, when O'Neill arrived at Celtic Park, the midfielder flourished, helping the team towards a domestic treble before breaking his leg in an SPL game at St Johnstone in March 2001.

Petrov was an integral part of the Celtic team which reached the Uefa Cup final in 2003 where Porto defeated the Hoops in extra-time in Seville.

But the Bulgarian stunned the club at the end of last season when he handed in an official transfer request, which was immediately rejected.

Both Celtic manager Gordon Strachan and chief executive Peter Lawwell have since reiterated their desire to hold on to the influential player for the Champions League this season.