Defending champion Great Britain was back with two members of their winning team, taking the qualifying heats with a world leading time. South Africa set the African continental record as they qualified winning the other heat. In a familiar situation, despite having the gold and silver medalists on their team, USA struggled with their handoff, completing their handoff at the end of the third zone and missing disqualification by inches or a favorable judge's decision. USA was the slowest qualifier into the final, just .08 ahead of Italy setting their national record in the adjacent lane. Because of the poor qualification position, USA drew lane 8. Instead of a substitute anchor runner, they went with their "A" team, putting in 200 meter champion Noah Lyles. Lyles spent the 2019 season coming back after slow starts, essentially demonstrating his superior top end speed. In a relay with a rolling start, his slow starts are negated. USA put the fastest starter, now the fastest man in the world, Christian Coleman in the blocks running against GBR's fastest turn runner Adam Gemili.
Race
Coleman did his part, gaining rapidly on China's best starter Su Bingtian to his outside. With a smooth handoff, as Justin Gatlin took his first step, he was ahead of China meaning USA would have no traffic interference for the rest of the race. One lane inside of Coleman, Gemili also did his job, keeping GBR close. Shuhei Tada for Japan also gained on World Relays champion Brazil.
On the second leg, Gatlin separated from Xu Zhouzheng and Zharnel Hughes also lost a little to the Olympic champion, but USA was right where GBR could watch them. Mike Rodgers had to hesitate to get the baton from Gatlin, but with USA's history, there was no disaster. GBR's handoff was also hesitant, with Richard Kilty having to decelerate to not run out of the handoff zone, but Japan passed quickly to former junior world record holderYoshihide Kiryū to keep them close. Through the turn, Rodgers separated from Kilty, Kiryū also gained with Japan passing in second place and South Africa was pulling close to Brazil to create a traffic jam. USA handed off cleanly to Lyles, as if they had practiced the handoff in advance. Japan handed off to their national record holder Abdul Hakim Sani Brown, GBR handed off to Nethaneel Mitchell-Blake, South Africa gave it to #6 on the season Akani Simbine and Brazil had Paulo André de Oliveira. And they were off to the races.
With a metre and a half advantage, Lyles expanded it to three metres by the finish. Lyles crossed the line holding the baton in the air in victory. Mitchell-Blake gained slightly to battle Brown for the medals, taking silver by a half a metre. Behind them de Oliveira came back on Simbine to nip South Africa at the line.
USA's 37.10 tied Jamaica's rescinded Usain Bolt/Asafa Powell powered 2008 Olympic team for the third fastest ever and the American record. Great Britain's 37.36 tied two more Bolt led Jamaican World Championship teams from 2013 and 2015 for the sixth best ever and the European record. Japan's 37.43 moved them into #14 in history, #4 as a country and the Asian record. And Brazil moved to become the #8 country, just behind South Africa's now #7 place from their faster race the trials and set the South American record improving on the one they tied in the trials. In all four continental records and nine national records among the 16 team event.
Records
Before the competition records were as follows:[2]