Ghana reached the African Cup of Nations final for the first time in 18 years after Asamoah Gyan's first-half header gave them a 1-0 victory over Nigeria on Thursday. The Stade Rennes striker, who also notched the winner in the quarter-final win over hosts Angola, scored midway through the first half for his third goal of the tournament. Ghana last qualified for the biennial tournament's final in 1992 before losing to champions Ivory Coast. They will meet the winners of Thursday's other semi-final tie between Egypt and Algeria while Nigeria will face the losers in the third-place playoff. A dull and cautious first half saw both sides struggle to create goalscoring opportunities, with defenders having the upper hand. Ghana needed a set piece to go in front after 21 minutes when Gyan rose at the near post to head home Kwadwo Asamoah's corner. The Black Stars then sat back to defend their lead, giving the Nigerians little room to mount threat. The Super Eagles wasted a clear-cut chance on 28 minutes though when Peter Odemwingie's mis-hit shot found Obafemi Martins inside the area but the Wolfsburg man's shot was straight into the body of keeper Richard Kingson. Nigeria piled on pressure in the second half but their forwards could not deliver. Martins repeatedly ghosted behind Ghana's defense to latch onto some long balls from midfield but failed to score the decisive equalizer. He came closest on the hour mark when he was picked out by a superb pass from John Obi Mikel but Kingson's timely interception thwarted his effort.