JOHANNESBURG, Sept 16 (Reuters) - Nigerian import Onyekachi Okonkwo steered his South African club Orlando Pirates into the semi-finals of the African Champions League at the expense of his former team on Saturday.A curling shot from the midfielder in the 30th minute gave Pirates a 1-0 win over Enyimba of Nigeria in the last of the Group B matches. Pirates finished second in the group behind Ivory Coast champions ASEC Abidjan, who drew 0-0 with Ghana's Hearts of Oak in Obuasi on Saturday. Enyimba had just needed a draw in the match in Johannesburg to progress to the semi-finals and had several chances in the game to score but were let down by poor finishing. Apart from Okonkwo's pin-point shot, Pirates were also poor in front of goal. Congolese international Blaise Mbele missed a chance to extend the lead at the end of the game when he was one-on-one with the goalkeeper but he hit his effort wide. Pirates now host the winners of Group A in the first leg of the semi-finals at the end of the month. Group A will be decided on Sunday when the final two matches are played in Algeria and Tunisia. ASEC Abidjan are up against the runners-up in Group A. ASEC will play at home in the second leg of the semi-final next month. Their goalless draw in Obuasi on Saturday meant that Hearts of Oak finished bottom of the standings without scoring a single goal.