Diego Maradona's criticism of River Plate's pitch has landed the Argentina coach in hot water.
River Plate, whose Monumental stadium hosts Argentina's home World Cup qualifiers, wrote to the Argentine Football Association (AFA) demanding to see Maradona's contract as national coach and his medical tests.
The club are upset after Maradona slammed the state of the pitch before and after the national team's 1-0 win over Colombia 10 days ago.
Maradona called the pitch a quagmire and added sarcastically: "they could also paint the stands".
"River presented letters at the AFA in which we referred fundamentally to the national team coach's exaggerated and in some respects insolent remarks about River which have deeply hurt us," club vice president Julio Macci said.
"The pitch was all right. Many said that from one to 10 they would give it seven points," he told La Red radio station.
"Given that he is the national team coach, we thought his remarks out of place ... It's bad for Argentina's image in the world."
AFA President Julio Grondona put an official apology to River Plate on the body's website.