Arsenal forward Alex Iwobi scored twice as Nigeria stunned Argentina 4-2 in Krasnodar, Russia, on Tuesday, while Sergio Aguero was reportedly taken to hospital after fainting in the dressing room.

Sevilla midfielder Ever Banega and Manchester City striker Aguero fired Argentina, playing without the rested Lionel Messi, into a 2-0 lead after 36 minutes.

But Leicester City striker Kelechi Iheanacho pulled one back on the stroke of halftime before Iwobi netted a second-half brace either side of a goal from Brian Idowu to shock the South Americans.

Local media later reported that Aguero was transported to hospital after fainting at halftime, with the forward undergoing medical tests as a precaution.

"We played really well in the first half but something went wrong after the interval," Argentina head coach Jorge Sampaoli said. "We just failed to convert our chances today.

"I'm concerned that we cannot find a worthy replacement for Messi."

Nigeria boss Gernot Rohr praised his team's resolve after the three-time African champions had looked doomed to defeat.

"There were two completely different halves. The opening period was very hard. One could believe the match was already over after Argentina scored their second goal," said Rohr. "But we managed to perform a comeback.

"After we scored we rearranged our play in the break and performed much better in the second half. My players are mentally strong, they showed strong will. I'm very happy with their perforance."