Ruud van Nistelrooy believes his ex-strike partner Wayne Rooney should focus on his game and not be distracted by allegations surrounding his private life.
The Manchester United forward has been in the headlines of late because of reported off-field indiscretions and some, including manager Sir Alex Ferguson, believe it has affected his form.
Rooney has just one Premier League goal this term from four starts, but Van Nistelrooy believes he should only be judged by his displays on the pitch.
Van Nistelrooy has played in Spain, Germany and England along with his homeland in Holland and believes only Premier League players are scrutinised to such an extent on and off the field of play.
"I think that the most important thing for a footballer is that you focus on the game," he told Sky Sports News HD.
"That's obviously the main thing. In England there is the press that looks into other parts as well.
"That doesn't happen in other countries really. You get judged by your performance on the pitch and that's how it should be.
"I think that's the way it should be. You have to live with that if you play in England."
Van Nistelrooy believes Ferguson would not select players who were not focused or in the right frame of mind mentally.
"The players I played with at United were always focused. They still are," he continued. "He can (handle it). He's proved it."
The Dutch striker has kept tabs on United after leaving Old Trafford and he felt Rooney's output improved last year as he operated as an out-and-out forward without worrying too much about the defensive side of his game.
"What I saw with him last year was that he didn't use as much energy as he has in the past," he said.
"He conserved his energy more. You used to see him tackling in his own box.
"He got in the box more. He got around more where he is dangerous."