Sergio Aguero faints at half-time, taken to hospital during Argentina v Nigeria

The 29-year-old had become his nation’s joint-third highest scorer in history when he found the net in the first half, but he fell ill in the changing room at the break.

The Argentine Football Federation (AFA) said in a statement that Aguero was taken away for routine examinations but added: "The player is well".

Nigeria fought back from a two-goal deficit to win the match 4-2.

"It's a difficult game to explain," said Argentina coach Jorge Sampaoli. "We could have been 3-0 or 4-0 ahead in the first half and we went in with a 2-1 lead."

"My biggest worry was the way the team played when we were behind. I know we are capable and have the individual talent to be able to get out of these situations and I'm worried about what happened tonight."

"We played an incredible first half but we lost our way in a match which could confuse a lot of people."

Argentina staggered through their World Cup qualifying campaign, only clinching their place at the finals with a 3-1 win in Ecuador in their final match.