The disconsolate midfielder left the field in tears, and looked so woebegone he had to be escorted around by Obinna Nsofor as he came through to meet the media.
"I made a mistake, he hit me with the ball and I went hard on him. I made a mistake and I want to say sorry to my players and to all Nigerians," Kaita said.
Vasileios Torosidis, who was involved in the scuffle with Kaita, appeared to make a meal of the challenge, and at the end, could not decide if he had been hit on the face or the leg.
"I think it was my face and my leg," he said with a sheepish smile.
Nigeria now need to win their next game against South Korea, and hope that Argentina beat Greece to progress to the group stages.