Thomas & Mack Center, Las Vegas - Eight division world champion Manny Pacquiao showed he still has plenty of energy by dominating Jessie Vargas in a WBO title fight on Saturday — and retired five division beltholder Floyd Mayweather Jr. was there to see it with a ringside seat and was shouting instruction into the ring.

After the fight was over, Maywearther gave Pacquiao a thumbs up from ringside as the Filpino star stood on the ropes and looked down at the crowd.

Pacquiao, who turns 38 next month, floored Vargas in the second round en route to a one-sided victory that allowed him to reclaim the WBO welterweight title which both he and Mayweather held previously.

It is a title that Pacquiao surrendered when he lost last year to Mayweather in the richest fight in boxing history. The retired Mayweather’s appearance at ringside Saturday, at Pacquiao’s request, will certainly stir talk of a Pacquiao-Mayweather 2.

Pacquiao beat Vargas with a unanimous decision victory to capture the WBO belt for the third time. Vargas won the vacant belt in March by knocking out Sadam Ali.

But both Pacquiao, and his promoter Bob Arum, were non-committal about a second fight with Mayweather. Pacquiao had to skip the event because of a cut from a head butt that needed 16 stitches to repair.

Another fight that fans are demanding is a showdown between Pacquiao and WBO/WBC junior welterweight champion Terence Crawford, who was also sitting ringside in Las Vegas. Crawford would like to do that fight at 140-pounds, as would Pacquiao's trainer Freddie Roach.

"I'm gonna go back home to the Philippines and back to work in the senate, and then I'll talk to [Top Rank promoter] Bob [Arum] about my next fight," Pacquiao said. "I don't know who the fight will be -- whoever the people want me to fight. I am not picking an opponent. Whoever my promoter gives me, I will fight. Anybody at 147. Crawford at 140? Not a problem."