She clocked 51.60 seconds - a season’s best - during a frantic evening session in Birmingham.
Elliot Giles had just won a dramatic 800m bronze after he was promoted to third. The USA’s Drew Windle, who initially came second, was disqualified after an apparent push to allow Giles, who came fourth, onto the podium.
However, CJ Ujah suffered a dismal end to his World Indoor Championships after he was disqualified for a false start in the 60m semi-finals.
The 23-year-old was tipped to challenge for a medal but clearly reacted before the gun in his heat.
He stormed out of Arena Birmingham following his disqualification, having prioritised the Championships in the midlands over next month’s Commonwealth Games in Australia.
It was a repeat of the 2015 European Indoor Championships final in Prague when he also false started to allow team-mate Richard Kilty to win.
Ujah, a 4x100m world champion, clocked 6.57 seconds to win his heat in the morning session.
After his morning heat Ujah had said: “You’ve got to just come out and take it round by round. I just wanted to run a little faster than I did here at trials a couple of weeks ago.
“I wanted to get the legs turning over quickly which I did, so I’ll go back to the hotel now and rest up.
“It’s coming to the moment now and I have to be ready. The last few weeks have been good build-up but just part of the training. It is all about tackling that next round now.”