Floyd Mayweather issued a challenge to boxing rival Manny Pacquiao yesterday, daring the Filipino icon to “Step up Punk” in a posting on Twitter.

Mayweather hopes to entice Pacquiao into a May 5 bout in Las Vegas, a mega-fight showdown between the world’s top pound-for-pound fighters, one that boxing fans have wanted to see for years.

“Manny Pacquiao I’m calling you out let’s fight May 5th and give the world what they want to see,” Mayweather posted on Twitter.

The move comes as Pacquiao promoter Bob Arum is visiting his fighter in the Philippines to discuss who the Asian superstar should take on next and Mayweather awaits the June 1 start of a 90-day jail sentence on domestic violence charges.

Arum originally said that Mayweather was not among possible next foes for “Pac-Man”, listing Mexico’s Juan Manuel Marquez, Puerto Rican southpaw Miguel Cotto and Americans Tim Bradley and Lamont Peterson as candidates.

But that was assuming Mayweather was going to start serving his sentence last week. Instead, a judge postponed Mayweather’s trip behind bars until after his already-booked May 5 fight.

“My Jail Sentence was pushed back because the date was locked in. Step up Punk,” Mayweather also tweeted.

Pacquiao, who has won 15 fights in a row over the past seven years, has told Filipino media that he wants the opportunity to fight Mayweather to be a top priority.