World champions Argentina suffered a 2-1 defeat to Paraguay as South America's big guns struggled in CONMEBOL World Cup qualifying Thursday.
It started well for Lionel Scaloni's team, also reigning Copa America champions, as they grabbed an early lead through Inter Milan striker Lautaro Martinez.
Enzo Fernandez lofted a lovely ball over the Paraguay defence into the path of Martinez who drove in a low finish only for his celebration to be cut short by the linesman's flag.
But a Video Assistant Referee review found that Martinez had been just onside and over-ruled the on-field decision giving Argentina an 11th-minute lead.
It was an advantage that was to last just eight minutes though as the home side drew level in spectacular fashion.
Gustavo Velazquez whipped in a cross and Antonio Sanabria leapt in the air and fired past Emiliano Martinez with a brilliantly executed bicycle kick.
Filled with belief and roared on by the crowd in Asuncion, Paraguay battled hard in what was a scrappy encounter.
Two minutes after the interval Omar Alderete grabbed what proved to be the winner, rising at the back post to head home a cross from Inter Miami midfielder Diego Gomez.
Argentina struggled to create openings with Lionel Messi largely neutralized although the eight-time Ballon d'Or winner did provide a cross for Valentin Castellanos but the substitute could not keep his header down.
Despite the loss, Argentina remain top of the standings on 22 points while Paraguay move into the sixth automatic qualification spot.
Five-time World Cup winners Brazil are in third place on 17 points - the top six South American teams qualify automatically for the 2026 World Cup.
Venezuela are in seventh place on 12 points and the seventh-place team will enter an Inter-confederation playoff for a spot in the tournament, which will be co-hosted by the United States, Canada and Mexico.
Ecuador are in fifth spot after Gonzalo Plata scored twice in a 4-0 win over Bolivia in Guayaquil.
Veteran striker Enner Valencia opened the scoring with a 26th-minute penalty before Plata's brace either side of half-time.
Alan Minda wrapped up the win with a shot from outside the box.
Uruguay face Colombia and Peru host Chile in Friday's qualifiers.
RESULTS
Ecuador 4 (Enner 26-P, Plata 28, 49, Minda 61) Bolivia 0
Paraguay 2 (Sanabria 19, Alderete 47) Argentina 1 (Lautaro 11)