Sydney McLaughlin obliterated her own world record to win women's 400m hurdles gold on Wednesday as skateboard star Sky Brown stayed on track to become the youngest Olympic champion in history.
McLaughlin powered home under the beating Tokyo sun in 51.46 seconds, with world champion and 2016 Olympic gold medallist Dalilah Muhammad claiming silver in 51.58 after another classic duel between the two dominant American hurdlers. Muhammad made a flying start in the lane outside her compatriot and rival but McLaughlin produced a late burst of speed to claim victory.
Muhammad, 31, also ducked inside the previous world record, with bronze medallist Femke Bol of the Netherlands just outside the 52-second mark. It came a day after an epic duel between Karsten Warholm and Rai Benjamin in the men's 400m hurdles which ended with Norway's Warholm winning in another world record time.
Canada's Damian Warner leads the way in the men's decathlon after three events while defending champion Nafi Thiam of Belgium tops the heptathlon standings after two events, with British world champion Katarina Johnson-Thompson in third spot.
In the evening session, pre-Games favourite Noah Lyles take on exciting 17-year-old US compatriot Erriyon Knighton and Rio 2016 silver medallist Andre de Grasse in a hotly anticipated men's 200m final.
Canadian De Grasse was the fastest man in the semi-finals with a national record 19.73, 0.1sec quicker than another American, Kenneth Bednarek.
Jamaica's Elaine Thompson-Herah made history on Tuesday, winning the 200m to complete the first women's Olympic sprint "double-double" after her earlier triumph in the 100m.