Title favourites Sally Pearson of Australia, Kenyan David Rudisha and New Zealander Valerie Adams all sailed through their respective Olympic qualifying heats on Monday.
The trio nailed world golds in Daegu, South Korea, last year and again showed their class in front of another packed morning session at the Olympic Stadium in east London.
Pearson clocked the leading time in the 100m hurdles, timing 12.57sec to finish ahead of American duo Lolo Jones and Kellie Wells, and Turkey's two-time defending European champion Nevin Yanit.
"I was quite nervous and I'm glad it's over," said Pearson. "I can go back and fix my body for tomorrow now.
"There's no more work to do. This is it. Tomorrow is another day at the office and I'll see what I can do."
Also making the cut was reigning Olympic champion Dawn Harper, but one to miss out was 2009 world champion Brigitte Foster-Hylton, the 37-year-old Jamaican clipping a hurdle to limp home well off the pace in 13.98.
To the crowd's dismay, there was no Jessica Ennis, the recently-crowned heptathlon gold medallist having opted out of the individual hurdles despite running a blistering 12.54sec en route to winning the mutli-discipline event.
Australia's Sally Pearson competes in the women's 100m hurdles heats at the athletics event of the London 2012 Olympic Games on August 6. Title favourites Pearson, Kenyan David Rudisha and New Zealander Valerie Adams all sailed through their respective Olympic qualifying heats.
But home hopes will remain with US-born Tiffany Porter, who timed 12.79sec.
"I came out here and executed," she said. "I'm looking forward to the semi-final."
In the men's 800m, Rudisha avoided any trouble around his two laps by leading from gun to tape, barely breaking sweat as he won his heat in 1min 45.90 ahead of Qatar's Sudan-born Musaeb Balla.
"The track is fast, it looks good," said Rudisha. "I had a relaxed race and I'm happy with my performance.
"We will work as a team if we all get to the finals. Teamwork has always been the core part of the Kenya team.
"It affected the marathoners because they had to wait for each other and in that way they sacrificed the gold but in this race we have a strategy and we know what to do in the final if we get there."
Rudisha said teammate Ezekiel Kemboi's victory in the men's 3000m steeplechase on Sunday was a "good omen".
"We waited for that one gold but that is going to open the way for many more golds," he predicted.
"Many people are disappointed that Kenya had not won a gold up to yesterday but comparing the performance in Beijing with this one, Kenya are one medal up at this stage."
Kenya's David Lekuta Rudisha reacts after competing in the men's 800m heats at the athletics event at the London 2012 Olympic Games on August 6. Title favourites Rudisha, Australian Sally Pearson and New Zealander Valerie Adams all sailed through their respective Olympic qualifying heats.
The world record holder (1:41.01) will be joined in Tuesday's semi-finals (with the final scheduled for Thursday), by Ethiopian tyro Mohammed Aman and Sudan's world silver medallist Abubaker Kaki.
Adams overcame an administrative blunder that almost cost the reigning women's shot put champion the chance to defend her title in London.
An "administrative error" meant Adams' name was missing from the official start list for her competition, the New Zealand Olympic Committee (NZOC) said, leaving officials scrambling to get her included so she could take part.
It did not reveal who was responsible for the mistake but said in a statement that it was taking the situation "extremely seriously" and was "committed to finding out exactly what occurred".
Adams, 27, who also won gold in Beijing in 2008, is New Zealand's leading hope for a track-and-field gold medal.
After fouling her first attempt in the qualifiers, she nailed 20.40m on her second to qualify for the final in Monday's evening session behind arch-rival Nadzeya Ostapchuk of Belarus (20.76m).