Benitez allowed the Australian winger to leave Anfield on a free transfer in 2008 after five injury-ravaged years at the club, but despite suspicions in England that Kewell would never regain full fitness, he has found his career rejuvenated since joining Turkish club Galatasaray.
Kewell's agent, Bernie Mandic, puts the player's renaissance down to receiving specialist treatment in his homeland, and so impressed has Benítez been by the former Leeds player's recovery that he has sought advice in an attempt to seek a cure for the groin injuries which have plagued striker Fernando Torres.
"We had Rafa Benítez call him the other night inquiring who these guys were because Fernando Torres has got such major problems now," Mandic said. "We have also had Jonathan Woodgate's physio inquiring about him, because he is apparently almost unfixable.
"But look at Liverpool. Why is it that, over so many recent years, usually around November, lots of their key players are injured? It is always soft-tissue injuries. How come other clubs do not have that sort of dilemma? And why do their players recover quicker? There are logical reasons."
Mandic blames Liverpool's medical staff for costing Kewell "3½ years" of his career after his controversial £5 million move from Elland Road.
"He gets treated in Australia now because we have the best medical staff in the world," said Mandic. "People are now wondering how he has recovered when everyone in England thought he was a broken toy."