Four hours after he stepped out of the ring at the MGM Grand Garden Arena, Manny Pacquiao stepped on to the stage about a mile away at the Mandalay Bay Events Centre and belted out a high-tempo version of La Bamba.

Boxer, singer, actor, politician, there seems no end to Pacquiao’s interests, each one carried out with a warm boyish enthusiasm.

Boxing can be a cruel sport. While Pacquiao, a trilby sitting atop a huge bandage, performed to a crowd of about 4,000 mostly Filipinos — who had paid $40 (about £24) each to hear their hero sing — Miguel Cotto, his beaten opponent, was undergoing a full body scan in hospital to ensure that the beating he had received left no lasting damage. Pacquiao’s bandage was a result of a procedure to drain his ear — film stars and musicians are better without cauliflower ears.

With his band flown in from the Philippines, Pacquiao’s set was a mix of up-tempo pop and slushy ballads, and included a rendition of the 1970s classic, Sometimes When We Touch, performed in a duet with Madonna Decena, a former semi-finalist in Britain’s Got Talent.

The stage at the Mandalay Bay has hosted bands from Bon Jovi to the Spice Girls, but, while Pacquiao’s singing showed that he has more talent in his fists than his vocal chords, it is worth remembering that the others are unlikely to have warmed up by being punched in the face.

But then, Pacquiao takes his boxing, as with his singing, very seriously. Each day after training he would go to rehearsal, with the full blessing of Freddie Roach, his trainer. “When he does his music, he’s calm, he’s relaxed and it gets his mind off the boxing,” Roach said. “As long as he’s not playing basketball, that’s all I care about.”

What was most obvious was how much fun Pacquiao was having. “We will sing in English, so that everyone can understand the words,” he said, grinning from ear to ear, before wailing out a ballad about lost love.

Pacquiao’s hero status continues to grow and his rise is remarkable, considering he started out living on the streets of his native General Santos City, having run away from home aged 12 after a neighbour ate his dog. He puts his rise down to his Catholic faith, but his fighting spirit was there from an early age.

Resituto “Buboy” Fernandez, a lifelong friend, said Pacquiao’s fists came in handy when he was 7 and selling doughnuts on a street corner. “Everyone had their own area, but if you got a bigger area you could make more money,” Fernandez said. “So Manny would fight the other boys. I think he would mostly win.” From miniature doughnut shark to world idol to, some think one day, his country’s President. All achieved with grace and that engaging smile. On the evidence of his second performance on Saturday, he really is the fighting man’s Will Young.

• Yuri Foreman, who is studying to be a rabbi, became the first Israeli world champion as he took the WBA light-middleweight title on the Las Vegas undercard. He was a unanimous points winner over Daniel Santos, of Puerto Rico.