Nigeria became the first side to advance to the knockout stage of the Africa Cup of Nations on Wednesday as they beat Guinea 1-0, having taken more than an hour to break the deadlock for the second straight match. Nigeria centre back Kenneth Omeruo scored the only goal of the game after 73 minutes, rising unchallenged to head home a corner from Moses Simon at the Alexandria Stadium. It was Nigeria's second Group B win from two games, but was another testing encounter after they beat Burundi 1-0 in their opener having taken 77 minutes to break down the resilient rookies. Nigeria's six points guarantees progress to the last 16 after a major improvement in their form from the opening game of the tournament. Guinea are third in the table with one point after they drew 2-2 with Madagascar in their opener. (For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)