Argentina beat England 19-14 to win the United States Sevens tournament in San Diego and claim only their second ever IRB Sevens World Series title after first seeds South Africa were eliminated in the semi-final by a brilliant England side that wiped out a 12-0 deficit after just 90 second to win 22-17.
England and South Africa are now joint-top on 60 points in the series standings with four tournament completed and four to play - eight clear of New Zealand on 52. Argentina are fourth with 48 ahead of Fiji, Kenya and the USA, who take 12 points from their home event.
The Pumas' only previous Cup success also came in California, in Los Angeles in 2004, and this most recent victory blasts wide open the race for the 2008/09 World Series.
In the Cup final Tom Biggs and Ben Gollings both scored first half tries for England either side of one by Argentina captain Santiago Gomez Cora.
Trailing 14-5 at the break, the Pumas quickly asserted pressure on the Englishmen after the restart and scored tries through Martin Rodrigues and Lucas Amorosino, before their famous defence kicked in to hold England at bay for five minutes.
To reach the final the Pumas built an early 12-0 lead against US but Nese Malifa and Chris Wyles each scored converted tries to edge the hosts clear, before Santiago Gomez Cora grubbered through and pounced on the loose ball to score the winner.
South Africa were eliminated in the semi-final on Sunday when a brilliant England beat them 22-17 after trailing 0-12 after the first 90 seconds.
South Africa were on the scoreboard from the kick-off after a 70 metres run and this was followed immediately by a try by his captain Mpho Mbiyozo for a 12-0 lead after 90 seconds.
But then near faultless rugby by England, played at tremendous pace, saw Ben Gollings and Ollie Phillips square it up at 12-all at the break, with tries by Tom Biggs and Phillips again putting England 10 points clear at 22-12.
Paul Delport made it 22-17 with 20 seconds remaining, and that was that for the outplayed Boks after a brilliant semi-final.
Results:
Finals: Cup: Argentina 19 England 11
Plate: New Zealand 22 Kenya 7
Bowl: Australia 40 France 0
Shield: Canada 31 Mexico 7
Semifinals: Cup: England 22 South Africa 17,
Plate: New Zealand 24 Fiji 12, Kenya 17 Samoa 12
Bowl: France 17Scotland 12, Australia 26 Wales 24
Shield: Canada 31 Mexico 7, Uruguay 26 Japan 10