South Africa's Ruben Ramolefi, 33, broke his own national record yesterday during the heats of the 3000m steeplechase at the world athletics championships in Daegu.
He finished second in the heat in 8min 11.50sec, improving by 0.13sec on the previous mark of 8:11.63 that he set in Monaco two years ago.
Defending champion Ezekiel Kemboi of Kenya was fastest of the qualifiers, holding off Ramolefi to win the heat in 8:10.93.
Ramolefi is the eighth-fastest of the 15 athletes in Thursday afternoon's final.
"I told myself just to run comfortably and be rhythmic," said Ramolefi, who controlled the race from the start. "I didn't try to be technical about it, I just trusted my body.
"On the big screen I saw that we were quite a group, so I thought that I needed to spread the group to leave us less work at the end."
Former national champion Cornel Fredericks and South African record-holder LJ van Zyl were in good form in the heats of the men's 400m hurdles, qualifying comfortably for today's semifinals.
The 21-year-old Fredericks finished second in the fastest of five heats, but was given the same time - 48.52sec - as Britain's David Greene.
Van Zyl, the fastest in the world this year, won a tough heat in 48.58sec to beat a field which included former Olympic gold medallist Felix Sanchez of the Dominican Republic and defending champion Kerron Clement of the US.
South Africa's Wenda Theron set a personal best in the heats of the women's 400m hurdles, clocking 56.13sec as the 17th-fastest of the 24 qualifiers for today's semifinals.
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