Farah wins world 10,000m title for third time in a row
Mo Farah lit up the London Stadium once again as he survived a brutal collective effort from his rivals to storm to his third consecutive world 10,000 metres gold.
Roared on by a capacity crowd as loud as anything experienced here during his Olympic triumphs five summers ago, the Briton almost fell twice late in the race as an epic contest developed, before kicking down the home straight in trademark fashion to finally pull away.
These are Farah's final track championships, and not since his golden run of victories began seven years ago has he been tested like this.
Yet he proved himself equal to those physical and tactical challenges, his young son and three daughters joining him on the track afterwards as the celebrations rolled around the arena.
Uganda's Joshua Cheptegei was in his wake for silver and Kenya's Paul Tanui third, the winning time of 26 minutes 49.51 seconds just three seconds off Farah's personal best.
The time reflects the pressure Farah was put under, the pace surging in the middle stages, the moves coming from all around as his rivals threw everything they had at him.
Much has changed since 2012, with Farah's controversial coach Alberto Salazar the subject of an US Anti-Doping Agency investigation, but this felt like a throwback to those golden nights in east London, the stadium awash in partisan fever and Union Jacks.
Farah could win a seventh world gold when he competes in the 5,000m
As he came out onto the track for the start Farah had gestured at the crowd for more noise, and he did so again as the contest began to develop.
Coming into this final he had eight consecutive 10,000m victories under his belt, including gold at the Olympics in 2012 and 2016, two golds at the Worlds and another at the European Championships.
And from the start his rivals looked to work together to upset his plans, Cheptegei and Kenya's Geoffrey Kamworor taking the field through the first 1,000m in a brisk two mins 39 secs.
Kamworor, Tanui and their fellow Kenyan Bedan Muchiri hit the front at 4,600m, throwing in a 61-second lap before Ethiopia's Abadi Hadis surged again.
Farah was content to sit in sixth and seventh as Eritrea's Aron Kifle then took it up, followed by Uganda's Timothy Toroitich and then Cheptegei again, and only at 800m did the 34-year-old make his move.
With 600m to go Farah still led, and he would not relinquish it despite being tripped so badly with 300m left that he took a step off the track.
But there was no stopping him, the capacity crowd screaming him home once again.
Farah received his medal shortly after beating Cheptegei (left) by less than a second, with Tanui third
Farah, who will begin the defence of his 5,000m crown in heats on Wednesday, described his 10,000m win as "amazing".
He told BBC Sport: "I had to get my head around it and I got a bit emotional at the start. I had to get in the zone.
"It wasn't an easy race. I work on everything and it's been a long journey.
"What a way to end my career in London. It's special.
"Anything is possible in life if you train hard. To all the kids out there, if you want to be like me it is possible if you work hard."
Farah's time was his best since 2011
2005 marathon world champion Paula Radcliffe: "It was the best of all of Mo's victories. Yes, 2012 kicked it all off but tonight they really took it to him and made it a tough race and he handled it."
BBC 5 live commentator Mike Costello: "It was astonishing the discipline he showed to win and he looked so in control it was almost like his great hero Muhammad Ali to George Foreman in the Rumble of the Jungle when he said 'is that all you've got?'"
1976 Olympic 10,000m bronze medallist and BBC commentator Brendan Foster: "That was the best ever. Mo's last ever 10,000m in a Championship in his favourite stadium. He was hurting in the middle. He brought the crowd to their feet. He is a ruthless running machine."
Bolt through with 'very bad' run
The other great retiring superstar, Usain Bolt, remains on course for his own golden farewell after easing through the first round of the 100m.
Bolt was far from happy with his start - afterwards describing the starting blocks as the worst he has used - but recovered to win his heat in 10.07 secs.
All three Britons - CJ Ujah, James Dasaolu and Reece Prescod - will join him in the semi-finals, Prescod clocking a new personal best of 10.03 for third in his heat.
Britain's Laura Muir, Jess Judd, Laura Weightman and Sarah McDonald all qualified safely for the semi-finals of the 1500m on a fine opening night for home athletes.
In one of the most competitive events at these championships, British record holder Muir ran a controlled race to come through her heat, with both Judd and McDonald producing personal bests as the big medal contenders - Faith Kipyegon, Caster Semenya and Genzebe Dibaba - underlined their threat.
Holly Bradshaw is also into the pole vault final after a first-time clearance at 4.50m.