World champion Asbel Kiprop's relentless pace proved too much for his rivals, including Mo Farah, as the Kenyan clocked the fastest 1,500 metres time since 2004 at the Monaco Diamond League meeting on Friday.
Part of Sebastian Coe's new job as head of world athletics will be to shift the conversation about his "ostensibly clean" sport from doping to spectacular performances, he said on Sunday.
Athletics is set to reintroduce four-year doping bans even though the move risks alienating the sport from the world anti-doping authority (WADA), officials said on Wednesday on the eve of the world championships.
Usain Bolt once again produced his best when it mattered most to retain his 100 metres world title and reassert his status as the number one sprinter on the planet at a rocking Bird's Nest Stadium on Sunday night.
Britain's Mo Farah stormed to victory in the 5,000 metres on Saturday to secure an unprecedented third successive distance double at major global championships.
The Jamaican was cagey when asked about the latest batch of positive tests and though he stopped short of condemning his rivals, he did issue a reminder of the principle that every athlete is responsible for what they put into their body.
Usain Bolt returned to the scene of his triple Olympic glory and duly delivered for 60,000 camera-flashing fans as he overcame a slow start to win the 100 metres and give the London Anniversary Games the Friday finale it demanded.