Great Britain's women flirted with failure before securing gold in the team pursuit on day two of the Track Cycling World Championships in Cali, Colombia.
Joanna Rowsell, Laura Trott, Katie Archibald and Elinor Barker claimed Britain's sixth women's team pursuit world title out of seven and a first gold of the 2014 World Championships ahead of Canada.
The victory - in four minutes 23.407 seconds to the Canadian quartet's 4mins 24.696secs - so nearly did not happen as Barker's legs gave up on the final lap, with Trott fearing a collision which would have ended with half the British team sprawled on the track.
"At the end Elinor changed down the straight and I hadn't actually made it back on yet," said Trott, who, like Rowsell celebrated a fourth world title in the team event.
"I was shouting because I thought if she turned any quicker she'd take me out and then it'd be game over if I take her down.
"You get lucky sometimes I guess and that's what happened."
Barker added: "I just could not hold those wheels. I completely parked it up.
"It was a split-second decision. I just had to get out of the way and let the girls carry on with it.
"It was that close that we just would've lost it if I'd stayed on the front."
Olympic champions Britain won five of six world titles in the event over three-kilometres and with three riders - silver in 2010 the only blot on the record - and their dominance had shown little sign of abating with the addition of an extra kilometre and an extra rider this season.
Despite being world record holders and clear favourites, Britain felt under pressure from Canada in a close-run final.
Barker added: "We could feel them breathing down our necks a little bit, but we managed to pull it back in the end."
Archibald has been a revelation after joining the squad full-time at their Manchester training base in November and was selected ahead of London 2012 gold medallist Dani King, who was a reserve.
The 19-year-old from Milngavie, with red, white and blue dyed hair, became Scotland's first female world champion.
She said: "For a long time there's been the pressure of living up to your team-mates and knowing that they've been Olympic champions, world champions, time and time again and so it's good to have someone on your heels, not just bumping elbows with your team-mates."
The internal competition has also helped, with Rowsell paying tribute to King.
"She could've easily slotted in, but didn't quite make the selection, but she's been awesome support all week," Rowsell said.
Defending champion Jason Kenny had to settle for fifth in the men's Keirin behind France's Francois Pervis, while Fabian Puerta of Colombia was roared on to silver.
Kenny recognised his bid was over after a collision which saw Germany's Maximilian Levy tumble to the track.
The 25-year-old from Bolton, who has a day off on Friday before the two-day sprint competition this weekend, said: "(The crash) just left me floating around at the top of the track and totally out of the race."
Head coach Shane Sutton had targeted a haul of six medals from the 10 Olympic events and Kenny's result meant Britain have two medals from five Olympic events with five remaining.
Becky James' run of World Championships medals came to an end as she finished seventh in the women's 500m time-trial, a non-Olympic discipline.
The 22-year-old from Abergavenny had won medals in five successive World Championship events - four in 2013 in Minsk and team sprint bronze on day one alongside Jess Varnish - prior to competing in the two-lap event.
Despite a personal best of 34.021 she had to settle for a minor placing as Miriam Welte of Germany won gold in 33.451.
Ireland's Martyn Irvine claimed silver in the men's 15km (60-laps) scratch race as Ivan Kovalev of Russia won gold.
Irvine fought valiantly in defence of his title, but ultimately came up short.
"I'm getting a bit of a greedy head - I always want gold now, but I'll take silver," Irvine said.
Ireland's Ryan Mullen was fourth in the men's individual pursuit in 4:24.626 as Alex Edmondson (4:22.582) of Australia won gold.