Manny Pacquiao and Floyd Mayweather fought in the "Fight of the Century" almost three years ago and now the 40-year-old Pacquiao wants to avenge his 2015 defeat.
After retaining his WBA world welterweight title on Saturday, the Filipino challenged five-weight world champion Mayweather, 41, to a rematch.
The retired Mayweather was ringside in Las Vegas watching Pacquiao beat American Adrien Broner with a unanimous points win.
In the post-fight press conference Pacquiao was repeatedly asked about the prospect of fighting the American again.
"My message is I'm still active, and if [Mayweather] goes back to the ring and wants to challenge me, I'm a champion. Get back to the ring and we will fight again if he wants," Pacquiao said.
"If he wants to come out of retirement, then announce it and challenge me. I'm a champion and I don't pick any opponent. I'm just waiting to see who will challenge me, who will challenge for my belt."
Fight of the Century II on the cards
Tickets for Pacquiao and Mayweather's fight in May 2015, billed as the "Fight of the Century," were on sale for as much as $350,000 with American fans charged almost $100 for watching on television the most lucrative boxing match in history.
In the post-fight press conference, he said: "It's not always about the money, believe it or not. What more can the man do?
"He doesn't have the motivation, the desire. He's living the best life, traveling, running his multiple businesses, spending his well-hard earnings that he spent blood and tears on for years.
"He'll be 42 come February 24 and enough is enough. What good does it do to earn all that money but you can't stick around and spend it. He has had a phenomenal career, he has broken all the records and he has nothing to prove."
"If he wants to come out of retirement, then announce it and challenge me. I'm a champion and I don't pick any opponent. I'm just waiting to see who will challenge me, who will challenge for my belt," he added.
In 2015, the two boxers fought a highly-anticipated match which was eventually won by Mayweather. The tickets of the match were sold for as much as $350,000 and the American fans were charged around 100 for watching the clash on television.
Mayweather holds a 50-0 winning record in the professional bouts and has already announced his retirement from boxing. Pacquiao, on the other hand, is the only eightdivision world champion in boxing.
After his latest win over Nasukawa, Mayweather insisted that he remained retired, saying the fight had been "all about entertainment for the people."