Team GB have made it into the finals of the 4x100m relays in the women’s and the men’s competition. But there were tense moments for the favourites in the women’s race after the USA came perilously close to being disqualified, after a mistake in their second handover.

There was a shock in the men’s competition as Jamaica failed to qualify for the final after a series of botched handovers.

In the first women’s heat, the USA’s Melissa Jefferson started well, handing to Twanisha Terry but Gabby Thomas charged out too early, with the runner changing the baton just in time. The 100m silver medallist, Sha’Carri Richardson, had a lot to do on the anchor leg, but put on the boosters to power her team over the line in first position with a time of 41.94sec. The USA women took gold in 2012 and 2016 but were second behind Jamaica in Tokyo.

The GB team – Bianca Williams, Imani-Lara Lansiquot, Amy Hunt and Desiree Henry – took a comfortable win in the second heat. With smooth handovers that belied the trouble British quartets have had in this event, the team posted 42.03.

Hosts France fought hard for second place in 42.13, while the reigning champions, Jamaica, came in third in 42.35. The top three from each heat getting a guaranteed spot in Friday’s final.

Great Britain, who were bronze medallists in the past two Games, will be considerably strengthened by the return of Dina Asher-Smith and Daryll Neita for the final.

The USA took the first step towards ending their men’s 4x100m relay drought, qualifying fastest from Thursday’s heats.

The GB team of Jeremiah Azu, Louie Hinchliffe, Richard Kilty and Nethaneel Mitchell-Blake finished third in the first heat. First place was taken by USA, as they hunt the title for the first time since Sydney 2000. Fred Kerley, who was involved in the botched changeover that ended their Tokyo hopes, ran a strong second leg, handing to the green-haired Kyree King, and Courtney Lindsey brought them home well clear in 37.47. Akani Simbine ran a fast last leg to take South Africa to second in 37.94, just ahead of Britain (38.04).

After qualifying, Kilty said he thought they would manage a quicker final. “We skip breakfast, to burn calories and prioritise sleep,” he said. “So we’re like vampires in the night-time.

“We’re going to come out and we’re ready for blood tomorrow night.”