JOHANNESBURG - One of three all-west African quarterfinal clashes, between Ivory Coast and Nigeria, will headline the first knockout round of the 2013 Africa Cup of Nations this weekend.The Ivorians are again fancied to win this competition after they lost last year’s final to an inspired Zambia, while Nigeria’s Super Eagles boast an impressive record in this tournament even if they struggled to reach the knockout stage here.The other all-west African quarterfinals will see Togo battle Burkina Faso, while Ghana take on surprise package Cape Verde.On Saturday, hosts South Africa will seek revenge against Mali in Durban for a place in the semifinals.Nigeria skipper Joseph Yobo said Sunday’s showdown in Rustenburg against the Elephants will always be one of the biggest ties in Africa."It does not come any bigger than this in Africa and, of course, we will be the underdogs against the highest ranked team in Africa. But the game will only be decided on the pitch,” said Yobo, who is at his sixth tournament."Everyone expects us to lose this match, but as players we just put our heads down and come Sunday we will cause a little upset against the Ivory Coast,” added Chelsea winger Victor Moses, who scored twice against Ethiopia to set up the tie.The sides have met five times at the Nations Cup finals with two wins for Ivory Coast, one for Nigeria, and two draws.The Ivorians have won the most recent match-ups – 1-0 in the semifinals of the 2006 Cup of Nations in Egypt and a 1-0 win in Sekondi-Takoradi in a group game at the following tournament in Ghana.Nigeria edged it on penalties after a 2-2 draw in a famous 1994 semifinal in Tunis and also pipped their regional rivals 1-0 in a group tie in Algiers in 1990.The other draw was in a group match in Lagos in 1980 with the Eagles going on to win their first continental trophy.The fairy tale run of the Blue Sharks from Cape Verde will face a stern test against one of the tournament favourites, Ghana, on Saturday in the Indian Ocean city of Port Elizabeth.The west African islanders sent Cameroon packing in the qualifying tournament and have surpassed most expectations by reaching the knockout rounds on their debut appearance.