Under - fire Nigeria manager Stephen Keshi has admitted that the first half performance of his charges in their 3 - 2 loss to Congo was nothing to write home about, and has suggested that the antics of the opponents affected the composure of his team in the last 45 minutes. <br /><br />Celtic utility man Efe Ambrose opened scoring for the African Champions, who then conceded three goals before a late goal from Warri Wolves Gbolahan Salami decided the game&rsquo;s outcome.<br /><br />&ldquo;I told them they were not playing their game. They were not themselves, they were not playing, they were second to the ball and they needed to change the mentality,&rdquo; Stephen Keshi told reporters.<br /><br />&ldquo;They came back in the second half and you could see the difference. But if you are playing a team like this, they are going to come hard and park the bus. And that&rsquo;s what they did in the second half. Who won&rsquo;t do it?<br /><br />&ldquo;I can understand the frustration, the Congolese team delaying the game, killing the game. It became an anger problem and its part of the game.&rdquo; <br /><br />Nigeria will clash with South Africa in Cape Town on September 10 in their second Group A fixture.<br />