Britain's Jason Gardener claimed gold in the final of the men's 60m at the World Indoors with a blistering display in Budapest.
The 28-year-old Gardener flew out of the blocks to ease through in a time of 6.49 seconds.
American sprinter Shawn Crawford, Gardener's leading rival over the distance, finished in second place.
Crawford's countrywoman Gail Devers sprinted to glory in the women's 60m in a time of 7.08 secs.
Elsewhere, Kelly Holmes continued a strong first day for the British as she comfortably won her 1500m semi-final in a time of four minutes, 11.15 secs.
The Kent-based runner had spent much of the early part of the race keeping out of trouble at the back of the bunch before sprinting clear of her rivals.
There were other strong British outings from Jo Pavey and Chris Tomlinson on day one.
Pavey qualified for the final of the 3,000m with second place in her heat and will be joined by Hayley Tullet.
Tomlinson produced a season's best of 7.96 metres with his final jump to sneak into the long jump final.
Pavey, still an indoor novice, said: "I found my heels were being clipped a
lot more than I'm used to and thought I might fall over at any moment.
"It's only my third indoor race and the first one where the field has been so
Catherine Murphy and Helen Karagounis both qualified for the semi-finals of the 400m.
Murphy held on for second in her heat with a time of 52.18secs, while Karagounis ran a personal best of 52.66secs to qualify as a fastest loser.
The first British success of the evening's events saw Jo Fenn qualify for the final of the 800m, finishing her heat in second.
But Mozambique's Maria Mutola was the pick of the athletes in the five heats, clocking the second fastest time of the season.
Ireland's Adrian O'Dwyer exceeded expectations by reaching the final of the men's high jump with a leap of 2.27m.
But Britain's Adam Potter missed out in the men's 400m despite a brave attempt to take the lead at 250m.
John Mayock's chances of making a sixth successive World Indoors final were blown away when he was barged in the 3,000m.
He is hoping that a protest from British team management will be upheld and gain him a place in Saturday's final.
Mayock said: "I should have easily qualified as there were eight of us away but I was pushed right out of the way by the Moroccan."
Devers comfortably stormed to glory in the final of the women's 60m.
The 37-year-old sprinter proved too strong for Belgium's Kim Gevaert, who was second, while Yuliya Nesterenko snatched bronze - both women running 7.12secs.
Britain's Joice Maduaka, though, failed to even make it to the final.
Vita Pavlysh netted the first gold of the championships in the women's shot putt, beating Svetlana Krivelyova by more than half-a-metre with a winning throw of 20.49m.
Portugal's Naide Gomes was also a gold-medal winner, sealing the pentathlon title with 4,759 points.