Canada won the men’s Olympic 4x100m relay on Friday after the US, the hot favourites, messed up a changeover yet again and were disqualified.

Andre de Grasse ran a superb last leg to bring the Tokyo silver medallists home in 37.50 seconds for their second gold in the event following their 1996 win.

Akani Simbine ran a terrific last leg to get South Africa silver in an African record 37.57, as did Zharnel Hughes to earn Britain bronze in 37.61.

Christian Coleman gave them a great start but ended up virtually colliding with Kenny Bednarek at the first handover. They recovered to finish well down the field, but were disqualified as the exchange was illegal.

Since 1995, in the Olympics and World Championships, the US have now had 11 dropped batons, disqualifications or bans.

Their women teammates, however, raced to the gold medal in the 4x100m relay, capturing their 12th title in the event.

Melissa Jefferson, Twanisha Terry, Paris Olympic 200m champion Gabby Thomas and Sha’Carri Richardson clocked 41.78 seconds after getting the baton around the track with no major mishaps. Britain got silver and Germany claimed bronze.

Paulino best

Dominican Republic’s Marileidy Paulino surged to victory in the 400 metres to add the Olympic gold to her world title.

Paulino had been unbeaten over the distance at four consecutive meets this year. Bahrain’s Salwa Eid Naser took silver and Poland’s Natalia Kaczmarek earned the bronze.

Kenya’s Beatrice Chebet won the women’s 10,000m. Italy’s Nadia Battocletti took silver and Dutchwoman Sifan Hassan claimed bronze.