Brazil star Neymar has said his team had to play in "inhuman" conditions during their 0-0 draw with Bolivia in high-altitude La Paz on Thursday.
Brazil have already booked their place at next summer's World Cup but they could have had another win in qualifying had Bolivia keeper Carlos Lampe not kept Neymar and his teammates at bay.
After the game, however, the Paris Saint-Germain attacker posted photos on social media of the Brazil squad wearing oxygen masks in the dressing room, complaining that conditions in Bolivia were not up to his usual standards.
"Inhuman to play in such conditions. Pitch, altitude, ball... everything bad," he wrote on Instagram.
At 3,640 metres (11,942 feet) above sea level, La Paz is the world's highest capital city, and Brazil seemed to feel the effect of the altitude in the final 20 minutes of the match.
"I felt a little tired -- it's normal," Manchester City forward Gabriel Jesus said. "[It's the] first time I played in altitude like this. To feel it, it's normal. We managed to play, set the rhythm. Unfortunately, the ball didn't go in today.
"It's [time] to rest so that in the next games we can play another good game and score goals. Physically it takes a lot. Possession of the ball is in relation to the field. That wasn't nice, but we can't complain. It's to enter the field and play, to confront problems."
In 2007, FIFA briefly banned international games above 2,500 metres, then adjusted the limit to 3,000 -- effectively singling out La Paz -- before lifting the rule a year later.
Meanwhile, Brazil defender Thiago Silva picked up a leg injury in the first half and was replaced by PSG teammate Marquinhos.
Thiago Silva, 33, had to be stretchered off after dropping to the ground with no one near him after 27 minutes of the match.
"Thiago felt pain in the back of his right thigh," Brazil boss Tite said after the game. "He couldn't continue. Early evaluations show a possible muscle injury. He will be re-evaluated in Sao Paulo and after we'll tell you what will be done."
Thiago Silva could now miss Brazil's final qualifier against Chile on Tuesday, while PSG will anxiously await an update on his fitness.
Any injury lay-off for the PSG captain would come at a bad time for the Ligue 1 leaders, who are due to play five games between Oct. 14 and the end of the month.
Their upcoming fixtures include a trip to rivals Marseille, a match against Nice -- one of last season's title rivals -- and two Champions League ties against Belgian team Anderlecht.