There is no doubting he will be remembered as one of the sport?s greats with world titles in eight different weight divisions.
But at the age of 37, with his career as an influential Senator in the Philippines, no stoppage win since halting Miguel Cotto in 2009 and three defeats in his last seven outings, questions are rightly being asked about what Pacquiao has got left now.
There is also the lacklustre display ? injured or not ? when he was completely outwitted by Floyd Mayweather Jnr almost 18 months ago in boxing?s richest bout.
This is a story you have heard before. A great fighter who cannot walk away and feels there is always one more big performance left in him.
It is a tale older than dirt, but Pacquiao believes it will not have the usual sad ending despite the growing evidence he is not the fighter he once was.
That fighter was the ?Pacman? who could beat opponents into submission with his pin-point combinations that pierced through guards with extraordinary ease.
He could also deliver one-punch knockouts in devastating fashion, as British ring star Ricky Hatton will know too well.
The Filipino banger managed all this while rising through the weight divisions from flyweight to as high as light-middleweight, beating ring legends such as Marco Antonio Barrera, Erik Morales and Juan Manuel Marquez along the way.
But he is no longer that force even though he looked sharp when he outclassed Timothy Bradley Jnr in April before his faux retirement that has lasted less time than most big-name fighters take off between bouts.
Now he is back after juggling training with political duties at home to face WBO welterweight champion Vargas.
?I want to prove that I am still one of the best pound-for-pound fighters,” Pacquiao said this week in the build-up to the clash at the Thomas and Mack Centre on the campus of the University of Nevada in Las Vegas.
?I feel I still have a lot to prove. I am not done with boxing. I will continue to keep fighting as long as I love boxing and boxing still loves me. I do not feel old. I feel like I am still 27.?
