Argentina, fresh from their exploits in Beijing where they beat Brazil on the way to Olympic gold, were confounded in their attempts to claim victory and move to the top of the 10-nation group after this seventh round of the 18-match series. Home fans in the Monumental stadium were subjected to the worst possible start after just 12 minutes when a mix-up caused defender Gabriel Heinze to put the ball past keeper Robert Abbondanzieri and into his own net.
In the same play, Abbondanzieri was injured and received five stitches in his knee and stand-in Juan Pablo Carrizo replaced him for the rest of the match. Argentina's Carlos Tevez, of Manchester United, was then sent off on 30 minutes for his second yellow card to make things even more difficult for the home side.
Sergio Aguero, who had replaced Angel Di Maria in the 45th minute, equalised for Argentina on the hour. Good work from Barcelona striker Lionel Messi to get past four Paraguay defenders, before releasing a long pass, set up Aguero to find the net.
Argentina coach Alfio Basile said afterwards: "Everything bad that could have happened did. We had the worst luck and the sending off of Tevez knocked us back. It was a strange match but I was not happy with the draw because I believe we deserved to win."
Paraguay now lead the group with 14 points from seven matches, two points ahead of Argentina on 12. Further matches to be played on Saturday area Ecuador versus Bolivia, Colombia against Uruguay and then Peru at home to Venezuela.