With a powerful closing charge over the final 25 metres, South Africa's Cornel Fredericks turned in an impressive victory in the 400m hurdles to give Africa its first victory of the day in the first track event of the competition.
Americas' Javier Culson, from Puerto Rico, was out quickest, clearly ahead by the second hurdle and had a big lead by the fourth. But he began to labour as he entered the final turn, an unintentional signal to Fredericks that the race was well within his grasp.
The pair were about even off the final barrier, but the momentum was clearly with the South African who forged ahead confidently to reach the finish in 48.34.
"I was focused on preparing for Marrakech to have the ability to add another title after my win at the African Championships and Commonwealth Games," said the 24-year-old, who collected the two titles within a 14-day period earlier this summer.
Kariem Hussein of Switzerland continued his impressive late 2014 campaign, following up his European title-winning run with a second-place finish here. He too passed Culson coming off the final hurdle to clock 48.47, a hefty improvement over his previous 48.70 career best that moved him to fifth on this season's world list.
Culson kept his form to hold on to third position in 48.88, with Europe's Rasmus Magi, from Estonia, fourth in 49.23 and Nigeria's Cristian Morton fifth in 49.65.
Fredericks and Morton combined for 12 points as did Hussein and Magi, putting Africa and Europe in a tie for the lead after one event.
Bob Ramsak for the IAAF