Team GB gold medal hopes Keely Hodgkinson and Josh Kerr both set up the opportunity to race for Olympic glory in Paris.
Hodgkinson, 22, looked effortless as she won her women’s 800m semi-final to progress fastest overall in one minute 56.86 seconds at Stade de France.
However, team-mates Jemma Reekie and 17-year-old Phoebe Gill did not manage to qualify for Monday night’s medal race.
Two days before their anticipated 1500m title showdown, world champion Kerr followed Norway’s Olympic champion Jakob Ingebrigtsen across the line in their semi-final.
Ingebrigtsen clocked 3:32.38 to take victory as Kerr chose to track his rival closely on the final lap, crossing just behind in 3:32.46.
Team-mate Neil Gourley (3:32.11) also qualified by finishing third in the second semi-final, won by American Yared Nuguse in 3:31.72, but George Mills failed to progress after coming through a repechage round.
European record holder Matthew Hudson-Smith and British team-mate Charlie Dobson both won their respective men’s 400m heats to qualify for Tuesday’s semi-finals.
Hudson-Smith, who will seek to upgrade his world 400m silver in Paris, began his bid for gold by taking a comfortable victory in 44.78.
Olympic debutant Dobson, 24, then edged out Belgium’s European champion Alexander Doom in 44.96 to move a step closer to the final, which takes place on Wednesday.
Olympic debutant Gill (1:58.47) finished fourth in her 800m semi-final while Reekie, fourth in the Olympic final in Tokyo three years ago, faded to fifth in her race in 1:58.01.