"Age is just a number". RL9 presented to Barca fans at Camp Nou

The Poland striker, who scored 344 goals for Bayern in 375 matches, joined Barca in a deal worth 45 million euros ($45.80 million) last month and was presented to thousands of fans at Camp Nou stadium in his number nine jersey on Friday. Lewandowski, who will turn 34 this month, said age did not matter to him as he looks ahead to a fresh challenge.

"It is only a number and physically I don't feel like I'm 33, nearly 34, because I know I can still play a few years at top level or even longer," Lewandowski told reporters. "I feel better even than when I was a 29-year-old. It's not the question we have to think about." Lewandowski and Bayern bosses criticised each other over the way they handled the transfer, with the player saying there had been lot of "politics" from the side of the club who were "trying to find an argument" to sell him. "If we're talking about that period, for sure, it wasn't easy for me to decide to leave Bayern after eight years, but I know for me and my family it was the perfect next step in my life and my career," he said.

Lewandowski won almost every domestic and international club title with Bayern, including eight league crowns, three German Cups, the Champions League and Club World Cup among others. The Bundesliga's second highest all-time scorer behind the late Gerd Mueller said that he would use his experience to guide Barca's young players. "This mix of young players and experienced players is important," Lewandowski said. "If I can help them with some words, not only technical skills on the pitch, but sometimes more with words I can tell them and explain because I've seen a lot in my life in football."

According to another former Bayern legend Jurgen Klinsmann, even without Lewandowski the Bavarians - who kick off their league campaign against Eintracht Frankfurt on Friday - remain favourites for a record-extending 11th consecutive Bundesliga title.

"Lewandowski's departure will change dramatically the dynamic of Bayern," Klinsmann told an international media round table on Thursday. "Losing him is a big deal, a big deal for the entire Bundesliga, to lose such a high profile player".

"But the solution for right now, putting pieces on more shoulders, is probably the right way to go right now. Overall as a roster it's the team in the Bundesliga, they are the favourites for another title," he said.