Sunderland assistant manager Eric Black says John Mensah can be a star at this year's World Cup.Mensah, on-loan from Lyon, is hoping to hold off his previous injury problems and line up for Ghana at the biggest footballing event in the world.Black told safc.com: "John can make an impression in South Africa, without doubt. "He's one of the most natural defenders you'll see and on his day he's up there with the best in the Premier League."I've seen him play several times for Ghana and they have some very good players. He can do very well if we can get him through the remaining games-then he can go to the World Cup and see what that brings."Black added: "John's taken everything in his stride. He has a great mentality, he's an exceptional defender and he's an experienced defender now, to a certain degree."He's quick, reads the game exceptionally well and he and Michael Turner are a great pair. John's getting a lot of the credit but Michael has been outstanding in the last few games."Source: Ghanasoccernet.com