"You could say (Cristiano) Ronaldo is hard work," Eckersley told the Sentinel. "He's world class, but I think he takes it easy in training, so it is hard to know exactly where you are on the scale against him.
"I remember one training session when I was against the first team, but had Keane on my side.
"Beckham kept whipping these crosses over and Keane was shouting at me to stop him.
"I said 'most of the Premier League can't stop him,' and Keane just gave me that glare of his while Beckham was off laughing."
However, as much as he enjoyed training with the stars, the Salford-born defender was more interested in playing first-team football than the status of playing for United.
He said: "I had been at United since I was nine, was playing every week in the reserves, but never really got the opportunity in the first team.
"I made my debut in the Carling Cup, but never got the chance after that. Manchester United are a club who can buy anyone they want, so I wanted to get out and get into the league."