Gordon Strachan has opened up on telling Roy Keane he would not be a regular starter at Celtic, stating the Ireland legend was "not okay with it".

The former midfielder finished his career at Parkhead after leaving Manchester United.

He made his debut in the 2-1 Scottish Cup defeat to Clyde but would go onto to win a League Cup and Scottish Premiership during his six months in Glasgow, playing 14 times.

And Strachan insists that while there was some initial awkwardness when breaking the news, Keane was receptive during his time in Glasgow and the two still have a good relationship.

Speaking to sweep.io, he said: "Roy trained with us a bit before the transfer window because he had been let go by Manchester United, so he got to know the lads for a fair period of time before he officially signed.

"Roy was a different kettle of fish, because you're talking about a world class player. When it became apparent that we could sign Roy Keane, I was amazed and thought it was magnificent.

"But I had a problem; we were unbeaten in so many games and I had [Neil] Lennon and [Stiliyan] Petrov in the middle of the park.

"I used to play with two wingers and a forward player that would come back in and drop off the main striker, so I had no idea how I was going to fit him in there. I had to speak to Roy Keane and tell him that he wasn't going to be starting.

"The conversation started with us just staring at each other over the table, and I was genuinely so excited to have him at Celtic with me and I was never interested in the circumstances as to why he left Manchester United.

"So I was honest with him and I said, 'Listen, it's great having you here, but if I'm picking a team tomorrow, you aren't in it.'

"Without hesitation, he said he was absolutely fine with that, even though I could see he absolutely wasn't okay with that.

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"But I have to say that I got on tremendously well with Roy and I still do to this day if we do TV work together.

"I find myself gravitating towards him."

The 66-year-old won three titles in a row while in charge of Celtic, as well as a Scottish Cup and two League Cups, along with reaching the last 16 of the Champions League twice.

He also had spells in charge of Coventry City, Southampton, Middlesbrough and the national side.

And Strachan revealed the two players that he feels were his best signings.

"In terms of pure skill, there are two who really stick out; Robbie Keane and Shunsuke Nakamura," he continued.

"Robbie was a complete one-off and he had natural intelligence and an ability to take things in at the first time of asking.

"We worked with him on a few things at Coventry, but it became evident he didn't need to be told things twice before they sunk in. 

"Nakamura was £1.6million and an absolute genius. He stopped playing at 44 if I'm not mistaken, and after watching one tape of him myself and the coaching team knew we had to sign him.

"One tape went to me, one to Jim Blyth, one went to Garry Pendrey and one to Tommy Burns.

"It was a unanimous decision by all of us. I have signed and managed better players, I must admit, but just his skill and his bravery were absolutely incredible.

"He set standards in training as well. After every single game, regardless of who we were playing, he would change out of his match day kit, get into clean training kit and go and do 45 minutes of strength work on his upper and lower body."

Strachan feels the Japanese midfielder helped change the culture around the training ground, pointing to the influence he had on his team-mates.

And he insists that sort of quality can be lacking at times when clubs are trying to recruit players.

He said:"It didn't matter if we were playing Livingston, Manchester United or AC Milan, he was the last off the training ground.

"Then he would come in at 8am and do weights in the gym with a fitness coach. Eventually, Aidan McGeady was in there, Shaun Maloney was in there, as was Gary Caldwell.

"He set a new standard in training which was phenomenal. That's something that data can't tell you, about the humility of the player and the environment they create as well.

"If your recruitment team doesn't recruit people like that, then you won't have a successful environment.

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"They need humility, they need a work ethic, they need to be good with people and have an intellect in order to learn and develop as a football.

"It's like in any business, you have to have the intellect to adapt and progress. Data is almost like the 'Emperor's New Clothes' in the sense that it is useful, but you have to literally decode it and check for traits such as their ability to deal with people.

"Data is the easy part, but you have to look beyond the numbers."