But the 2012 Champions Trophy winners discovered the USA had other ideas and having had a couple of early chances, the eventual winners took the lead when Shannon Taylor deflected in a pass at the far post.
Despite weathering something of an onslaught, especially in the second half, the US held on to record a victory as famous as their 2011 Pan American Games gold medal, when they beat the same opposition 4-2 in Mexico - their only previous win over Argentina in major competitions.
Meanwhile, Great Britain proved they have character to add to their silky skills as they defeated the Republic of Korea to register their second win of the tournament, a 5-3 success.
Nic White and Crista Cullen had given the hosts a 2-0 lead and although they were initially pegged back, Alex Danson restored the two-goal cushion.
However, Korea stunned the Riverbank Arena with two quick goals but GB bounced back with Georgie Twigg and Chloe Rogers scoring the goals which took them top of Pool A after two matches.
In other games, the Netherlands were 3-2 winners over Japan, while New Zealand overcame South Africa 4-1.
The game between Belgium and China finished goalless, and Australia defeated Germany 3-1.