CELTIC manager Neil Lennon paid tribute today to former team-mate Stiliyan Petrov as he retired from football.

The Hoops boss formed a formidable partnership with the Bulgarian during Martin O'Neill's highly-successful reign.

And the pair have remained in close contact throughout Stan's brave battle to successfully overcome leukemia.

Lennon said: "It's very sad that Stiliyan has announced his retirement from football.

"He was a fine footballer and enjoyed a magnificent career at Celtic and Aston Villa, as well as representing and captaining Bulgaria on many occasions.

"First and foremost, of course, is his health, and the news earlier this year that Stiliyan is in remission was a great boost for everyone.

"I'm sure that his characteristic determination, along with the fact he's surrounded by a loving family, will ensure he's a success in this next stage of his life.

"The words he has spoken today demonstrate his absolute courage and positivity and show exactly the kind of man he is.

"It was a pleasure to play alongside such a great footballer, but, for me, I'm even luckier to call him my friend."

Celtic Chief Executive Peter Lawwell added: "The thoughts and best wishes of the whole Celtic family are with Stiliyan, as they have been ever since we first heard the terrible news about his illness.

"I think the way he has coped with this and battled it, is in keeping with the type of character he is.

"Stiliyan was a great Celtic player in a great team who achieved wonderful success for the club, both in Scotland and in Europe.

"We all wish Stiliyan, Paulina and their family well as he retires from football."