Argentina dominated the match from start to finish, with Lionel Messi teasing and tormenting the Americans with his full bag of tricks, but they only converted one of their numerous chances.
That came late in the first half when Messi threaded the ball between the legs of the U.S. captain Carlos Bocanegra and Esteban Cambiasso blasted home a rebound from the edge of the six-yard box.
Despite being heavily marked, Messi threatened to extend his team's lead on several occasions, but the Americans scrambled well in defense and then snatched an equalizer in the 59th minute against the run of play.
"I think we had a great first half. At times, we were brilliant," Argentina coach Sergio Batista, speaking through a translator, told a news conference.
"I think the football we want to see was there, but we didn't finish that well."
A lapse in concentration was all it took for the Americans to square the ledger in front of an enthusiastic crowd of 79,000, which had been bolstered by the appearance of Messi.
A KNACK
Carlos Bocanegra headed a free-kick from Landon Donovan straight at the Argentine goalkeeper Mariano Andujar, who fumbled the ball at the feet of Agudelo.
The 18-year-old, who came on as a second half replacement, reacted first, slamming the ball into the net to register his second goal in just three international appearances.
"He's had a knack now for turning up in some good spots to score goals," American head coach Bob Bradley said.
Bradley admitted his team had been mostly outplayed by an Argentina side that controlled the ball for long periods, leaving the home side to survive off scraps off possession.
Messi had provided Bradley and his tacticians with headaches in defense but the coach said he was impressed with the way his players coped while under constant pressure.
"We came away with a good result against a very good team," Bradley said.
"We understood that the first half didn't go the way we wanted, but I was pleased with the way we responded."
For both teams, the match was the first of two games they are playing in three days to help prepare themselves for their respective continental championships they are hosting later this year.
The U.S. - hosts of the CONCACAF Gold Cup in June - face Paraguay in Nashville on Tuesday while the Argentineans will travel to Costa Rica as part of their build-up to the Copa America in July.
