Ghana captain Stephen Appiah has said he is fearful of the threat posed by his team's opening opponents, Serbia. Appiah has warned his teammates and fans not to look beyond Sunday's Group D curtain-raiser. "Everybody's talking about Germany," he said, referring to the group's top seeds. "But I'm scared about Serbia." "They are aggressive, technically they are good, they are arrogant, they have everything," he told the BBC's African Sports programme Fast Track. Ghana meet the Serbians in Pretoria on Sunday (day three of the tournament), before taking on Australia on 19 June and Germany four days later. "We're not even thinking about Australia or Germany now," he said. "We are just focused on Sunday's game." The 29-year-old Bologna midfielder, who has been repeatedly hampered by injury, has also said the loss of his good friend Michael Essien, remains a big blow for the Black Stars. "I'm really sad for him, because every player wanted to be in this tournament, but unfortunately he didn't make it. "I'm with him on the phone morning, afternoon and evening, because we are buddies," he said. "It's a big blow, but some of the younger [players] are ready to take [up] that position." Ghana reached this year's Africa Cup of Nations final in Angola with many of their under-20 World Cup-winning side after they were again struck by injury - including to Appiah himself. And the Black Stars skipper sees the World Cup as a perfect opportunity for those younger players to step up a level. "You can see it in the way they play, they are really hungry," he said. "In Angola they got to the final - that shows they can really do it if some of us are not there." Ghana's Serbian coach Milovan Rajevic has meanwhile dismissed any talk of divided loyalties. "I am 100 percent Ghanaian," he said. "I am a professional, my primary target is to win against Serbia and to qualify [for the next round]," he said. Serbia's own preparations have been disrupted by a change of training facilities, due to a worry about picking up injuries. They switched from the AW Muller Stadium in western Johannesburg to the University of Johannesburg's rugby stadium. "I think they put a surface down a few days ago, so the pitch has not yet laid down nicely," said Lazio defender Aleksandar Kolarov. "The surface was a bit unstable, so we were worrying about injuries." Credit: BBC