Hurdler Andy Pozzi led Britain's athletes through a successful second morning of the World Indoor Championships in Poland on Saturday.
Pozzi was the joint fastest qualifier from the heats of the 60 metre hurdles in Sopot, equalling his personal best of 7.56 seconds at the Ergo Arena.
And he was joined in Sunday's semi-finals by team-mate William Sharman, who won his heat in a new personal best of 7.59secs.
Pozzi was just 19 when he finished fourth in the World Indoors in 2012, but he suffered a hamstring injury later in the season and pulled up in his heat of the 110m hurdles at the London Olympics. His 2013 campaign was then ruined by a foot injury which required surgery.
"It's a great start," the 21-year-old said. "I was a bit concerned being in lane one with some of the fast guys on the other side of the track, but it allowed me to focus on my race and I could not ask for much more.
"It was not my best technically, I actually lost my rhythm around the second hurdle because the track is so fast."
Sharman added: "It wasn't a perfect race, but I'm delighted to win and record a personal best. Four meets, four PB's, but the target is the outdoor season so let's take it from there and see what happens tomorrow."
Asha Philip and Sophie Papps also advanced to the semi-finals of the women's 60m, Philip winning her heat in 7.18s and Papps second in hers in 7.22s, equalling her personal best.
"I'm glad it's out the way," former world youth champion Philip said. "I didn't want to take it too easy because you never know what can happen out there. I got through and that's the main thing. Tomorrow should be a good day."
Papps said: "I never come to a race and say I want to make the semi-final as I want to go as far as possible and that's the final. I'm just looking to run my best and if it gets me to the final, it gets me to the final. I just want to leave saying I did my best."
Murielle Ahoure of the Ivory Coast was the fastest qualifier in 7.09s, while defending champion Veronica Campbell-Brown advanced after finishing third in her heat in 7.22s.
Campbell-Brown was cleared to compete again in February after winning an appeal against a secretly imposed two-year doping ban.
The 31-year-old, who tested positive for a banned diuretic at the Jamaica Invitational meet last year, had originally escaped with just a public warning in October after a disciplinary panel in Jamaica ruled that her violation was not serious enough to warrant a ban.
But it recently came to light that the International Association of Athletics Federations (IAAF) stepped in to order a two-year ban which was not made public, only for Campbell-Brown to successfully appeal against the ban at the Court of Arbitration for Sport.
"When you don't compete for a while you are going to feel a little rusty but I didn't feel too bad," she said. "I have nothing to prove. (I'm) just doing what I love."
In the 4x400m relays, both the men's and women's teams led from start to finish to win their semi-finals, Conrad Williams shrugging off having to run an extra 120m after the recall gun went off accidentally on the first leg.
Michael Bingham, Jamie Bowie and Luke Lennon-Ford maintained the lead to clock a time of 3:06.09, with team captain Eilidh Child leading Shana Cox and Victoria and Christine Ohuruogu to victory in 3:30.60.