Even in Brazil's Copa America opener this year - a goalless draw against Costa Rica - Vinicius ended up being substituted halfway through the second half after not managing a single scoring attempt. After that, Brazil manager Dorival Jr changed tack and that decision paid back in a major way.
With Messi sidelined after complaining of a sore right hamstring, and coach Lionel Scaloni serving a one-game suspension, Argentina made nine changes to their starting XI at the Hard Rock Stadium.
For only the second time in history, South America's continental championship is being held at venues across the United States this year, offering a taste of what North America can expect when the 2026 World Cup is staged in the region in two years' time.
Vinicius terrorised Paraguay's defence with his pace and trickery as he scored two goals in an impressive display, a far cry from his performance in Brazil's 0-0 draw with Costa Rica in their opening group stage match, in which he was largely ineffectual.
Brazil's Vinicius Junior scored twice in his side's 4-1 Copa America victory over Paraguay in a Group D clash at Allegiant Stadium in Nevada on Saturday, bouncing back from a lacklustre display in his first game of the tournament.
Lionel Messi will miss Argentina's final Copa America group game against Peru after complaining of muscle tightness, team officials said on Friday.
Colombia marched into the quarterfinals of the Copa America on Friday with a confident 3-0 victory over Costa Rica in Arizona.
Argentina coach Lionel Scaloni and Chile boss Ricardo Gareca were suspended for one match each after their teams' late arrival to the field of play during the Copa America, CONMEBOL said in a statement on Friday.
Marcelo Bielsa believes Uruguay have more to do to mark themselves out as one of the favourites to win the Copa America, despite crushing Bolivia 5-0 to make it two wins from two games.
Uruguay will progress as group winners if they avoid defeat by USA.
A wasteful Brazil side dominated possession but were clueless on how to beat an ultra-defensive Costa Rica playing with a back five. They roamed around their opponent's box but were toothless, with just three of their 19 shots on target.
The defeat means the United States will almost certainly have to win or draw against group leaders Uruguay in their final group game next Monday to have any chance of advancing to the knockout rounds.
Mexico-based veteran striker Salomon Rondon stroked in the only goal from the penalty spot to seal all three points for Venezuela, who are top of Group B with six points from two games.
Lionel Messi may sit out Argentina's next Copa America game against Peru to rest a sore thigh with his team already qualified for the next round after two wins.
World champions Argentina showed their steel and killer instinct as they beat Chile 1-0 on Tuesday to book their place in the Copa America quarter-finals.
Just as it looked like Argentina would be made to rue their missed chances substitute Martinez pounced on a rebound from a corner and lashed home a right-footed shot in the 88th minute to ensure victory and a top-two spot in the group for the defending champions.
David's 74th-minute goal was Canada's first under new manager Jesse Marsch. Prior to Tuesday's victory the Canadians had failed to score in two international friendlies and their opening Copa America match against Argentina.
Brazil's poor performance in their goalless draw against Costa Rica in their Copa America opener on Monday has dampened the enthusiasm surrounding their new manager and a revamped squad headlined by Vinicius Jr.