Samoa's 78-4 win over France sent a striking message to their Rugby League World Cup rivals, with Sua Fa'alogo scoring four tries.
The Melbourne Storm player also made two try assists and five line-breaks after leaving the bench to play on the wing.
He replaced Brisbane Broncos winger Deine Mariner, who limped off with a hamstring injury in the 11th minute, shortly after scoring the match's opening try.
Mariner, 23, had already missed two months this year after compartment syndrome in his right thigh required six surgeries.
"You can see the emotion," Channel 7 commentator Corey Parker said. "It looks as though he knows his hamstring may not be good."
Samoa coach Ben Gardiner described the problem as hamstring "awareness" and hoped it was not serious. The tournament runs for only six weeks.
"It's one of those things," Gardiner said. "Being so early in the tournament and the fact we scored a few tries early, I just thought it was safer for him to come off and not put any pressure on it."
"We were planning for [Fa'alogo] to come on at some stage, and to his credit he went out and had a blinder."
Fans expressed sympathy for Mariner, with one writing, "Feel bad for Mariner. Hope his hamstring is not that bad," and another commenting, "Tough sport. Injuries are part of it. Harsh on players."
Samoa hooker Benaiah Ioelu scored twice, while halfback Jarome Luai made two try assists. France's squad included several Super League players.