Usain Bolt and Tyson Gay safely negotiated the first heats of the 100 metres on Saturday but former world record holder Asafa Powell had a real scare on the opening day of the world athletics championships.
The first medals were awarded in the men's 20km walk as Russia's Olympic champion Valeriy Borchin overcame hot conditions to take gold in the race that finished not, as is usual, in the stadium but at the city's Brandenburg Gate.
There was no question about the day's main draw, however, as the 100 metres men took their place at the head of the table.
World record holder Bolt barely broke sweat in the morning sunshine to cruise home in 10.20 seconds while Gay, the fastest man in the world this year, posted the best time of the morning with 10.16.
Powell, who has become something of a peripheral figure alongside the "big two" despite a season's best of 9.88, eased up extravagantly at halfway then had to accelerate at the end to scrape home third in his heat and avoid elimination by 200th of a second.
The Jamaican, who has earned an unwelcome reputation as a "championship choker" wore a nervous smile as he awaited the results on the stadium screen before the Q spared his blushes.
The biggest casualty of the heats was 2007 silver medallist Derrick Atkins of the Bahamas who could manage only 10.44 to finish fifth in his heat.
The second round takes place later on Saturday with the semi-finals and final (1935GMT)on Sunday.
In the walk Borchin hit the front shortly after the midway point and drove clear in the final 5km to win in one hour, 18 minutes, 41seconds.
China'sHao Wang took silver with Edgar Sanchez finishing strongly to claim bronze for Mexico.
All the big names in the men's shot advanced to Saturday night's final with Poland's Olympic champion Tomasz Majewski leading the way with a throw of 21.19metres.
The United States have won the event in six of the last seven world championships and have three men into the final, including defending champion Reese Hoffa and 2005winner Adam Nelson.
After the first two events of the heptathlon Briton Jessica Ennis led the way with 2267points from American Sharon Day.
Ennis, the favourite, clocked the fastest 100 metres hurdles with 12.94, the only athlete under 13 seconds, and cleared 1.92metres in the high jump, also the best in the field.
World record holder and Olympic champion Gulnara Galkina threw down the gauntlet in the women's 3,000m steeplechase by winning her heat in nine minutes 17.67seconds to qualify fastest for Monday's final.
However, Russian compatriot Yekaterina Volkova, the defending champion and 2005silver medallist, had a terrible run and failed to qualify.
There are two gold medals up for grabs later on Saturday in the men's shot and women's 10,000 metres, which is without 2005 and 2007champion Tirunesh Dibaba who withdrew on Friday with a leg injury.