LONDON - Jamaican Usain Bolt etched his name further into Olympic folklore by completing an unprecedented and sensational sprint double-double with a smooth 200 metres victory in the joint fourth fastest time ever run on Thursday.

Jamaica's Usain Bolt reacts as he wins the men's 200m final during the London 2012 Olympic Games at the Olympic Stadium August 9, 2012. Seen are Jamaica's Warren Weir (L) and Wallace Spearmon of the US. [Photo/Agencies]

The world's quickest man, whose imperious performances in London have blown away all doubts that he deserves the unofficial title of greatest ever sprinter, stopped the clock at 19.32 seconds for victory in his favourite event.

Bolt has now matched his stunning Beijing 100 and 200 crowns four years ago following his shorter-dash victory on Sunday.

Compatriot Yohan Blake, as he did in the 100 behind his friend and training partner, took silver in 19.44 and Warren Weir completed a Jamaican podium sweep with bronze in 19.84.

Showman Bolt crossed the line with his finger to his lips before doing a handful of press-ups on the track. Then, taking a photographer's camera, he took snaps of the crowd and Blake who was posing as "The Beast", the nickname Bolt afforded his younger rival.

The 25-year-old is the first man to win two 200 Olympic golds and, as he did in 2008, he will look to complete the treble in the 4x100 relay.

Bolt's winning time matched that of American Michael Johnson who set a then world record of 19.32 to win Olympic gold in Atlanta in 1996.

Bolt lowered that to 19.30 in Beijing before clocking a remarkable 19.19 at the Berlin world championships in 2009.

On a warm and windless evening with the electric atmosphere inside an expectant Olympic stadium already raised by Kenyan David Rudisha's 800m world record less than an hour earlier, Bolt, relaxed and smiling in the preliminaries, flew out of the blocks.

Drawn towards the outside in lane seven, Bolt glided around the bend and kicking powerfully down the home straight was always ahead of Blake.