A tired Mo Farah feels there is a target on his back following his Olympic 10,000m triumph, but vowed to give everything in his bid for an historic long-distance double in London.
Farah was made to work hard in his heat of the 5,000m, eventually finishing third in 13 minutes 26 seconds to reach Saturday's final.
"I am definitely tired and I think it showed out there," the 29-year-old said. "The legs didn't feel great but that is what happens. Hopefully I will recover well and look forward to the final, forget about what I have done and rest up."
Team-mate Nick McCormick actually ran quicker than Farah in the considerably faster second heat, but could only finish 12th in 13:25.70 to miss out on a place in the final as a faster loser. McCormick, 30, said. "I was finishing strong, I just learned on that penultimate lap you've got to stay in contact."
Elsewhere, Sophie Hitchon improved her own British record in the last round of qualifying to reach the women's hammer final. Hitchon was set to bow out after a first-round attempt of 67.21m and a foul in the second, but the 21-year-old then produced a superb throw of 71.98m, 37cm further than her previous best and enough for 10th overall.
"I was just proud to be on the team and to come here at a morning session, with a full crowd and throw a PB and a British record, it was amazing," Hitchon said.
Steve Lewis had an easier time in qualifying for the pole vault final, a single clearance of 5.50m proving enough to go through as one of the 14 qualifiers, meaning the 26-year-old can try to emulate his room-mate Greg Rutherford, the long jump champion, in Friday's final.
Britain's Lynsey Sharp also made it to the semi-finals of the women's 800m in impressive fashion, the Scot under pressure to justify her place after her selection for the 800m with only the 'B' qualifying time meant four athletes with the 'A' standard - Jenny Meadows, Emma Jackson, Jemma Simpson and Marilyn Okoro - missed out.
There was disappointing news for Daniel Awde in the decathlon, the 24-year-old being forced out with a knee injury after the second event, the long jump. Awde had set a personal best of 10.71s in the 100m to lie seventh overall, but then committed two fouls in the long jump and already looked to be struggling before managing 6.83m with his final attempt.
Awde said: "I'm in the best shape of my life. I was so ready for this to put on a good show, entertain the crowd. I was ready but my knee wasn't. Without being too arrogant, if the pain is enough to make me stop and pull out of my home Olympics, then it's too painful."