Nigeria midfielder Sani Kaita has admitted to having sleepless nights after his sending-off in the 2-1 Group B defeat to Greece. The Africans were leading when Kaita clashed with Vasileios Torosidis on the touchline, aiming a kick at his Greek opponent.

Kaita was shown a red card and Nigeria went on to concede two goals to put their chances of qualification for the knockout stage in jeopardy. "I cannot stop apologising to all Nigerians for making this costly mistake," said the 24-year-old.

"I couldn't sleep thinking about what my action has cost my country, but I hope we will win our next game (against South Korea) and qualify for the next round, where I hope to redeem my image with a good performance.

I couldn't sleep thinking about what my action has cost my country.

Sani Kaita, Nigeria midfielder

"I promise to put my life down on the pitch to ensure we go very far in this competition. And I promise that what happened will never happen again."

Hoffenheim forward Chinedu Obasi also has regrets after missing a relatively straightforward chance in the second half which would have put his side 2-1 up. "I was really disappointed in myself because I was a little bit too confident that I was going to score," he admitted.

"I have to get over it, and that is what the team should do as well. We have an important game coming up against Korea, and we have to win that and hope that Argentina win against Greece."