Kenya's David Rudisha lowered the 800 metres world record to 1min 41.01sec in Rieti in Italy yesterday, just a week after first breaking the record.
The 21-year-old, who broke the record that had stood for 13 years in Berlin eight days ago, when he ran 1min 41.09sec, powered down the home straight at the IAAF World Challenge meeting to better that mark easily.
Denmark's Wilson Kipketer set 1.41.11 in 1997 in Cologne, Germany, but Rudisha has suddenly ripped up the record books twice. Last year at Rieti he had told the crowd he would "return to do something great".
Rudisha, who made a surprise semi-final exit at the Berlin World Championships last year, is the son of Daniel Rudisha, who was a member of the 4x400m Olympics silver-winning relay team in Mexico City in 1968.
The small city of Rieti, near Rome, has a long heritage of hosting record-breakers, and Jamaica's Nesta Carter also ran the joint-fastest 100m this year to win the final in 9.78sec, equalling Tyson Gay's time at the London Diamond League meeting earlier this month.
The American Ryan Bailey and Jamaican Mario Forsythe ran personal bests of 9.88 and 9.95 for second and third while France's European champion, Christophe Lemaitre, set a national record of 9.97sec in fourth place.