Jamaica's Usain Bolt ran the fastest time of the year in 19.55 seconds to win a record fourth straight world 200 metres title and sweep the individual sprints at a major global championships for a fifth time.
Five days after beating Justin Gatlin to win the 100 metres, the 29-year-old Olympic champion and world record holder again proved too strong for in-form American, who finished second in 19.74.
Anasco Jobodwana took bronze in 19.87 for South Africa ahead of Panama's Alonso Edward, who was awarded the same time but lost out on a medal by two 1,000ths of a second. Jobodwana's time was 19.861 and Edward 19.863.
The victory gave Bolt a record-extending 10th world championship gold medal and he could yet win an 11th as part of Jamaica's 4x100 metre relay team on Saturday.
Bolt, who had only run one race at the distance coming into the championships after an injury disrupted season, once again produced the goods when it really mattered.
The 29-year-old got out of the blocks quicker than Gatlin on his inside and was already in front at the bend, where the American picked up speed and looked like he might threaten the champion.
Puffing his cheeks out and swinging his arms high, though, Bolt pounded down the home straight to victory, thumping his chest with his fist as he crossed the line.
Bolt and Gatlin had only faced each other once before in a 200 metres race, at the 2005 world championships in Helsinki where the American claimed his first world title in the event and teenager Bolt finished last.
Gatlin, 33, had gone unbeaten since 2013 in both sprints coming to Beijing and his was the world leading time that Bolt bettered to take the title.
Earlier, Allyson Felix of the United States won her ninth world championships gold medal and first at 400 metres.
The Olympic 200-metre champion set off by far the quickest of the eight women finalists to hold a commanding lead by 150 metres.
Off the final bend she was four metres clear of her nearest rival, Shaunae Miller of the Bahamas, who could not close the gap down the final straight.
Felix's 49.26 seconds winning time was the fastest in the world this year while Miller claimed silver in 49.67.