Berlin  - Usain Bolt shook off some early-morning cobwebs as he strolled into the second of the 200 metres at the world championships on Tuesday.

The Jamaican superstar Bolt won his heat in 20.70 seconds and disappeared swiftly afterwards, mumbling only "it is alright."

American Shawn Crawford led the pack with 20.60 seconds but not even the 2004 Olympic champion and 2008 silver medallist is considered a serious threat for Bolt.

Bolt won Olympic gold in a world record 19.30 seconds last year and on Sunday started his Berlin title collection with an awesome 100m world record run in 9.58 seconds.

Bolt, who turns 23 the day after Thursday's 200m final, should be unrivalled as defending champion Tyson Gay of the US withdrew due to a groin problem after getting 100m silver. Gay leads the 200 list with 19.58 seconds to Bolt's 19.59.

In other early morning action, world and Olympic champion Gerd Kanter of Estonia handily qualified for Wednesday's men's discus final with 66.73m. German rival Robert Harting even had 66.81m.

Two-time champion defending champion Jeremy Wariner and fellow-American Olympic champion LaShawn Merritt were set to run in the 400m heats.

The German home crowd was anticipating the women's high jump qualifying, with their biggest gold medal hope Ariane Friedrich aiming to make Thursday's final along with Croatian title holder Blanka Vlasic. (dpa)