Derek McInnes can still remember Murray Davidson's first training session at St Johnstone.

The Kilmarnock boss had signed the recently-retired midfielder and Dave Mackay in a double deal from Livingston.

And within minutes, McInnes knew he was onto a winner.

Aged just 21, Davidson clattered Martin Hardie and offered no apology to his new team-mate.

"I thought there and then that he would do for me," said McInnes of Davidson's immediate impact.

“Murray was brilliant for me and I will never forget his first training session.

“I remember him leaving one on Martin Hardie in a challenge and Martin was as hard as nails.

“Murray never even apologised and just got on with it.

“That has always stuck with me and I can still see it happening.

“I was keen to see if Martin reacted and he never.

“Murray was straight in the team after that and he scored against Hearts on his Premier League debut.

“He was different class for me and I can’t speak highly enough of him."

READ MORE: How daft laddie Barry Robson has proved Archie Knox wrong at Aberdeen

Davidson called time on his career at the end of the season, earning a hero's send-off on his final appearance for St Johnstone after a 14-year stay at the Perth club.

For McInnes, he leaves a legacy as one of the best tacklers the Scottish top-flight has ever seen - even if VAR might have said otherwise had he kept playing.

“He was always going to pick up injuries because of the way he played the game," McInnes added.

“He was relentless in his workrate and was one of the best tacklers this league has ever had.

“When he tackled you then you really knew you had been hit.

“He was a proper old fashioned player and he has probably done the right thing retiring as he couldn’t play with VAR now.

“He was fully committed and so brave. He was a brilliant boy and he had such an impact at that club.”

Reflecting on signing Davidson, McInnes recalled: “I signed both him and Dave Mackay from Livingston and both turned out to be brilliant buys. There were a few teams after them but we managed to get them both for £30,000 from Livingston.

“They were always asking me who cost what.

“When I was with Murray I would tell him he cost £25,000 and Dave cost £5,000.  When I was speaking to Dave it would be the other way round. In terms of value for money it was a brilliant piece of business."