Akinfeev fumbled a long-range Lee Keun-ho strike into his own net but Aleksandr Kerzhakov rescued a draw for Russia with an equaliser in the Group H clash at the FIFA World Cup on Tuesday.
Capello said it was just an unfortunate error from his shot-stopper and was pleased his team were able to fight back.
"Goalkeepers can make mistakes like any other player and today it happened to a great champion like Igor Akinfeev," he said.
"Fortunately we were able to make up for his mistake."
Capello, who turns 68 on Wednesday, said he was content with his team's performance despite them being below their best.
"We played a solid match and I'm satisfied with our performance," he said.
"My players reacted well after the opening goal and it was the best possible birthday present they could have given me. Even so, I'm a little disappointed because we could have won the game.
"We were very edgy at the start and we weren't able to play our usual football. Even so, we still created danger, without ever really managing to be at our best.
"The South Koreans did some good things as a team, especially in terms of possession, but we were able to keep them at a distance."