Moscow: American Ashton Eaton steered himself smoothly into pole position of the decathlon at the World Athletics Championships after the first three events on Saturday, including his least favoured shot put.
The 25-year-old kicked off the defence of his title with a leading 10.35sec in the 100m, a third-best 7.73m in the the long jump, and 14.39m in the shot put.
Eaton ended with 2,755 points with the high jump and 400m to come in the evening session. Sunday's second day of action features the 110m hurdles, discus throw, pole vault, javelin and the 1500m.
Eaton, only the second decathlete to go beyond the mythical 9,000-point mark, holds world records in both the decathlon (9,039) and heptathlon (6,645) and is looking to go one better than Daegu, where he won a silver medal behind teammate Trey Hardee.
Hardee sat in fifth on 2,634 after three events, while Germany's Michael Schrader was second (2,707) and another American, Gunnar Nixon, third (2,677), with Canadian Damian Warner in fourth (2,642).
French pole vault star Renaud Lavillenie had a slight flutter of nerves after fluffing his opening attempt at 5.65m before comfortably nailing his second effort.
Fresh from vaulting a world-leading 6.02m in the London Diamond League meet last month, the Olympic champion is desperate to better his bronze-medal showings in Daegu two years ago and Berlin in 2009.
Czech Jan Kudlicka was the only other athlete to clear 5.65m as the 10 other qualifiers for Monday's final all went through at 5.55m, including Lavillenie's younger brother Valentin.
But there was no place for Cuban Lazaro Borges, silver medallist in Daegu, who bombed out after clearing only 5.40m.
"It's nice that both my brother and I will be in the final," said Renaud Lavillenie. "It's always a pleasure to qualify for the final. You can be a favourite but pole vault qualifications always remain delicate.
"Our goal now is gold for me and a place in the top eight for my brother."
All the main favourites also progressed smoothly thought the first round of the men's 800m, sadly deprived of world and Olympic champion David Rudisha of Kenya, the world record holder out injured.
Ethiopian Mohammed Aman, the only runner to have a decent record against Rudisha, clocked the fastest time of 1min 44.95sec as one of the six heat winners, with the semi-finals on Sunday and final on Tuesday.
"I won the heat and I'm very happy," said Aman. "The track here is pretty fast so we can expect some good, fast results.
"I hope today's win will inspire me to do my best to bring home the gold medal."
Aman, who finished sixth at the London Olympics, will no doubt be up against it from Djibouti's Ayanleh Souleiman and a trio of Americans, Duane Solomon, Nick Symmonds and Brandon Johnson.
"It felt really good and very comfortable," said Solomon. "I just wanted to dictate the pace. Today was getting the legs to move again and Sunday will be really good."
Uganda's Ronald Musagala was also a heat winner, along with Frenchman Pierre-Ambroise Bosse.
Evening action at the Luzhniki Stadium sees two of athletics' biggest stars make their entry.
Britain's Mo Farah is odds-on favourite to claim gold in the men's 10,000m while Jamaican sprint star Usain Bolt faces his first outing at the stadium in the heats for the 100m, with the semi-finals and final to be contested on Sunday.
The day's other final comes in the women's marathon, featuring defending world champion Edna Kiplagat of Kenya against reigning Olympic champion Tiki Gelana of Ethiopia, who is looking for a first marathon title for her country.
There are also qualifying events for the hammer and high jump for the men, and 400m, 3000m steeplechase, and long jump for the women.