World champion and world record holder David Rudisha of Kenya ran into the 800 metres semifinals in his usual style from the front in his Olympic debut on Monday.
Rudisha was untroubled as he advanced in 1 minute 45.90 seconds.
He missed the 2008 Games for injury reasons but has since bettered the world record twice to 1:41.01, won the 2011 world title, and is the 2012 season leader with 1:41.54.
World champion Sally Pearson and the 2008 Olympic gold medallist Dawn Harper breezed into the semifinals of the 100m hurdles from which Jessica Ennis withdrew in the wake of her heptathlon gold from Sunday.
The Australian Pearson led the heats with 12.57 seconds and the American Harper went safely through in 12.71.
Also set for the morning session were the women’s 1,500m heats and qualifying in the men’s discus and women’s shot put.
The shot put was then one of five evening finals along with men’s 400m and 400m hurdles, and the women’s 3,000m steeplechase and pole vault, in which Russian world record holder Yelena Isinbayeva was aiming for an unprecedented third straight gold in the Olympic farewell ahead of the planned 2013 retirement.