Kipyegon, the double Olympic champion, has not lost over the distance for two years. Budapest is her sixth world championships and she now has a remarkable haul of three golds, two silvers and a fifth place on her debut in 2013.

Ethiopia's Diribe Welteji (21) was the best of the rest as she took silver in 3:55.69, with Sifan Hassan (30) of the Netherlands finishing well for bronze in 3:56.00.

Tausaga smashes personal best to take discus gold

Laulauga Tausaga (25) obliterated her personal best by over four metres to take a stunning world discus gold on Tuesday just as fellow American and hot favourite Valarie Allman (28) had been seemingly cruising towards the title.

Tausaga came into the final with a best of 65.46 metres but somehow found 69.49 with her fifth throw, before sprinting into the crowd to celebrate with her incredulous supporters.

Allman owned the top six throws of the season coming into Budapest, the best of them almost three metres better than anyone else in the field.

Unlike in Eugene last year, when she took bronze as China's Feng Bin (29) won a surprise gold, Allman appeared to stamp her authority on the competition with a first round throw of 68.57 metres – further than any of her rivals had managed all year.

She improved that to 68.79 in the third round and 69.23 in the fourth and seemed set for gold until her team mate's stunner.

Allman had a final chance to reclaim the lead but could not manage it, leaving Tausaga to take a victory throw when she could barely control her emotions with the tears streaming down her face.

Feng claimed bronze with a final round throw of 68.20.