It was another night to remember for Mo Farah in Beijing as he won the 10,000 metres with a stunning display of distance running.
The Briton became the first athlete to win six consecutive global track distance gold medals by putting on another masterclass to break the track record at the Bird's Nest Stadium.
Farah's Kenyan rivals threw everything at him, but were unable to contend with the defending champion as he showed a blistering turn of pace to win in 27 minutes 1.13 seconds.
Geoffrey Kamworor, the world cross-country champion, had to settle for silver, with his fellow Kenyan Paul Tanui filling the podium.
Farah had to deal with questions over doping amid accusations aimed at his coach Alberto Salazar " which he strenuously denied " in recent months, but let his running do the talking once again.
The 32-year-old, who was last beaten in a global track event in the 10,000m at the 2011 World Championships in Daegu, will take some stopping when he seeks to defend his 5,000m crown next Saturday.
Farah took centre stage after Justin Gatlin laid down a marker by clocking the fastest time in the 100 metres heats ahead of his eagerly awaited showdown with Usain Bolt.
The controversial American, twice banned for doping, has been tipped to dethrone Bolt in Sunday's final following a run of 27 consecutive victories and the 33-year-old stated his intent by clocking 9.83 seconds to ease to victory in heat six.
Six-time Olympic gold medalist Bolt had an opportunity to respond in the next heat and was clearly not at full tilt as he edged out Mike Rodgers in a time of 9.96secs at the Bird's Nest Stadium.
Defending champion Bolt, who celebrated his 29th birthday on Friday, will be hoping to rise to the occasion when it matters in the final as he eyes yet another title at the expense of Gatlin.
Asafa Powell was also quicker than his fellow Jamaican as he won the opening heat in 9.95secs, with Tyson Gay (10.11), Femi Ogunode (9.99) Trayvon Bromell (9.91) and Jimmy Vicaut (9.92) winning the other heats.
Jessica Ennis-Hill leads fellow Brit Katarina Johnson-Thompson in the heptathlon after strong showings in the 100m hurdles, high jump, shot put and 200m.
Ennis-Hill, competing in her first championship since the birth of her first child, leads the way on 4005 points, with Katarina Johnson-Thompson (3925) and Nadine Visser (3871) in pursuit of the Olympic champion.
A time of 12.91secs got Ennis-Hill off to a strong start in the 110m hurdles before she matched her season's best by clearing 1.86m in the high jump and threw 13.73m in the shot.
Johnson-Thompson then won the 200m ahead of Ennis-Hill to surge into second spot with three events to come on Sunday.
Christina Schwanitz was crowned shot put champion in her fifth World Championships as home favourite Gong Lijiao had to settle for silver.
Schwanitz won silver two years ago, but went one better with a throw of 20.37m as Gong could only manage 20.30m and American Michelle Carter took bronze (19.76).
Nineteen-year-old Ghirmay Ghebreslassie was the man of the moment on the first morning of competition as he became the youngest World Championships marathon winner in a time of 2:12:27.