Jamie Carragher claims Michael Owen shocked the Liverpool squad by "topping people all over the pitch" with some of the dirtiest tackles he had ever seen.
Carragher and Owen were teammates at the Reds' academy in the '90s, while the latter went on to score 158 senior goals for the club.
During his decorated Anfield career, Owen picked four major honours and clinched the Ballon d'Or in 2001 before joining Real Madrid three years later.
The striker is considered one of the finest English players of his generation, scoring 40 goals in 89 games for the Three Lions, and was renowned for his electric pace and clinical finishing.
But his reputation as a fresh-faced teenager was very different, as Carragher recalls Owen was so dirty his agent had to intervene to stop him making horror challenges.
Reds legend Carragher told the Quickly Kevin podcast : "We're in the youth cup and we get Man United in the draw and we've used decent centre forwards, just local lads.
But [Academy Director] Steve Heighway said 'That's not enough against Man United, I'm going to get this lad in, he's still at school, Michael Owen.'
"And I'd not really heard too much of him - he scored a hat trick against Man United in the youth cup. It was like 'Who is this kid? He's like s*** off a shovel.' He was so quick.
"But that Liverpool youth team was a tasty team in terms of physicality. I mean some of the tackles we did and got away with, but then Michael turned up and it was like 'Oh my god.'
"We were all like from the back streets of Liverpool and this kid from Chester has come in and you should have seen the tackles he was doing, he was just topping people all over the pitch, oh my god."
Owen made his senior Liverpool debut aged 17 and scored 23 goals in his first full season - but Carragher admits the young striker had still not grown out of his dirty-tackle habit.
What are your memories of Michael Owen's playing career? Have your say here.
"And if you remember, when he first got in the Liverpool team he was like that," Carragher added. "Remember that tackle he done on [Man United goalkeeper Peter] Schmeichel? He put his foot in.
"And he done a [two footed] tackle against Everton, I think on [defender] David Weir and honest to God, I've never seen anything like it.
"And I think one of his agents must have said 'Listen, you've got an image you've got to play up to you can't be doing this'.
"And he stopped tackling, he didn't do any of those bad tackles any more."
Despite his regular two-footed tackles as a youngster, Owen's talent was clear to see and Carragher knew his academy teammate would go far.
Carragher said: "He was the only player I can ever say who was a guarantee. Michael was the only one you knew was going to be a superstar."
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