Alex Iwobi’s second-half winner ensured Nigeria became the first African nation to qualify for the 2018 World Cup when their 1-0 home victory over Zambia on Saturday moved them into an unassailable lead in their group.Egypt can become the second country to book their trip to Russia next year if they beat Congo at home on Sunday and Tunisia stand on the brink of a place as they maintained their three-point lead at the top of their group with one match left to play.The other two groups remain in the balance and will be settled on the last match day in November. The African qualifiers come from the five group winners.Iwobi netted with a neat finish inside the box in the 73rd minute of an open contest in Uyo after both Wilfred Ndidi and Moses Simon had squandered earlier chances.Zambia were the only country still capable of catching Nigeria in Group B but needed an unlikely away win against the Super Eagles, who have now qualified for six of the last seven World Cup finals, missing out only in 2006.Nigeria advanced to 13 points with Zambia on seven, one ahead of third-placed Cameroon, who beat Algeria 2-0 in Yaounde earlier…