Former West Ham United defender Arthur Masuaku scored a vital goal as the Democratic Republic of Congo defeated Guinea 3-1 on Friday to reach the Africa Cup of Nations semi-finals. Masuaku netted direct from a free-kick on 82 minutes to give his country a two-goal advantage in the quarter-final and they will face hosts Ivory Coast or Mali for a place in the title decider.Mohamed Bayo gave Guinea a 20th-minute lead from a penalty which was cancelled by DR Congo captain Chancel Mbemba soon after in Abidjan.Brentford forward Yoane Wissa put the Congolese ahead on 65 minutes from the second penalty of the match, then Masuaku effectively settled the outcome. “This is not a Cup of Nations of surprises. It is a Cup of Nations of hard work,” France-born DR Congo coach Sebastien Desabre said before and again after the last-eight clash.When he took over last year, the Congolese were in danger of not even making it to the Ivory Coast after losses to Gabon and Sudan. Under Desabre, they won their remaining four qualifiers. History suggested that the first AFCON tournament meeting between the countries in 20 years would be close as three previous matches produced a 2-1 win for each and a 2-2 draw.The Congolese Leopards reached the last eight without winning a match. They finished runners-up to Morocco in Group F after three draws before edging seven-time champions Egypt via penalties. Guinea qualified as the best of the four third-placed qualifiers, then Bayo scored the second latest regular-time goal so far to eliminate Equatorial Guinea. – Guirassy on bench -Both coaches made one change from the last-16 starting line-ups with DR Congo promoting centre-back Henock Inonga and Guinea upgrading former Liverpool midfielder Naby Keita.Serhou Guirassy, scorer of 17 Bundesliga goals this season for Stuttgart, once again started on the bench for the Guinean National Elephants.In a first half as closely contested as anticipated, Guinea went ahead on 20 minutes when Bayo recovered having been fouled by Mbemba to convert the resultant penalty.The lead lasted only seven minutes, however, before captain Mbemba connected with a corner to the far post and rifled the ball past goalkeeper Ibrahima Kone from a tight angle. Guinea coach Kaba Diawara would have been slightly happier than his opposite number, Desabre, at half-time as his team had more possession and goals attempts. Having trailed to a penalty, the Congolese went ahead on 65 minutes from another spot-kick with Wissa scoring after Julian Jeanvier tripped substitute Silas Mvumpa.With 20 minutes remaining, Diawara introduced Guirassy, having early in the second half brought on 18-year-old Facinet Conte. A balanced quarter-final took a decisive turn when a free-kick by Masuaku near the touchline drifted into the net at the near post off the hand of surprised Kone.On Saturday, hosts and two-time champions Ivory Coast face Mali in Bouake and 1996 title-holders South Africa meet Cape Verde in Yamoussoukro in the other quarter-finals.