Zambia coach Herve Renard reckons Saturday\'s 3-0 quarter-final defeat of Sudan was \"the toughest\" hurdle for the Copper Bullets to overcome so far at the CAF Africa Cup of Nations. \"The quarter-final was mentally hard for those who haven\'t played since the start of the competition. When you\'re in the last four there are only two matches left and you\'re obliged to go in search of a medal,\" said the Frenchman here Sunday. Zambia booked a semi-final date for Wednesday with the winner of the quarter-final between Ghana and Tunisia, being played at Franceville in Gabon later today. Renard, who was assistant coach with Ghana when the Black Stars hosted the 2008 Nations Cup, added that his players had learned the lesson from 2010 when they were knocked out at the quarter-final stage on penalties by Nigeria. \"We\'d done well then but we lacked experience. You have to pay attention to the details and have a dynamic in the squad which wants to accomplish something big.\" He compared the Nations Cup to \"a marathon\". \"At the 30 kilometre marker we\'re telling ourselves there\'s another 12km to go, and when there\'s only three or four kilometres left you get a renewed spurt of energy. \"We\'re in the home straight. We have to recuperate a little more now - after four matches in two weeks a couple of the players are beginning to get tired. We have the chance of an extra day\'s rest (compared to their last four rivals). We\'ll watch the game today. Now, we don\'t have any more pressure on us.\" Zambia reached their first semi-finals in 16 years with goals from Stoppila Sunzu, Christopher Katongo and James Chamanga against ten-man Sudan. In his post-match assessment Renard said: \"All was not perfect today, but you have to be efficient, and in football that\'s the most important thing.\"