Laura Muir and Eilish McColgan both ran personal bests to reach Sunday's 5,000m final at the World Championships.
Muir, fourth in the 1500m final, made it through as a fastest qualifier despite struggling on the last lap.
However, her time of 14 minutes 59.34 seconds was quicker than the 15:00.38 McColgan turned in to finish fourth in her heat.
There was disappointment for Eilidh Doyle, who came in last in the final of the 400m hurdles.
"I was ranked eighth and I finished eighth but, for me, that was a bit of a messy race," said the Great Britain team captain . "My semi was a lot better than that.
"There was a fast time out there and I didn't quite get it right on the night."
Muir, who has a faster indoor time over the same distance, ended up in a heap on the finish line, looking spent, but the 24-year-old is confident she can recover.
"I know I'm better than that and hopefully I can show it in the final," she said. "I felt good out there apart from that last lap."
McColgan, 26, is now less than a second off the career best of her mother Liz, who was 10,000m world champion in Tokyo in 1991.
"I'm so much more confident this year," she told BBC Sport. "Training has been going really well and I haven't had the major injuries. I feel like it's all come together at the right time."
Fellow Scot Steph Twell finished 15th in 15:41.29 to be eliminated.
Lynsey Sharp qualified for Friday night's 800m semi-finals, while Chris O'Hare and Jake Wightman both advanced from the 1500m heats, with Josh Kerr missing out.
Sharp, the 2012 European champion, was second in her heat and says her fitness is improving all the time.
"I've honestly been like a caged animal all week, just desperate to get out and race after watching everyone, so I'm just really happy to get the first one out the way," said the 27-year-old.
"This season has been a bit up and down but I've persevered and got back to almost at my best.
"I'm definitely in the best shape I've ever been in, so it's just about executing it in a race."