Josh Kerr narrowly missed out on an Olympic gold medal in the 1500m final, despite finishing ahead of arch rival Jakob Ingebrigtsen.
The Edinburgh-born runner set a new Olympic record and took silver, being overtaken by Cole Hocker of the United States.
The highly anticipated showdown was billed as a head-to-head battle with Ingebrigtsen, but Hocker’s sprint down the home straight saw him take the surprise gold medal in a time of 3 minutes 27.65 seconds.
Norway’s Ingebrigtsen finished in fourth place with no medals after setting a breathtaking pace and leading for much of the race.
Yared N’Guse of the United States won the bronze medal, just one-hundredth of a second behind Kerr.
There was much talk beforehand about Kerr and Ingebrigtsen’s apparent dislike for each other after their abusive exchange last year.
Kerr’s time of 3:27.79 was a British record and the 26-year-old seemed content with his silver medal. He picked up the Union Jack and hugged fans on a knee of honour.
Trackside He admitted he had been concentrating on the gold medal but said he was “really proud” and it was a “great step in the right direction”.
Kerr, who beat Ingebrigtsen to win gold at last year’s world championships, will win bronze at the 2021 Tokyo Olympics.
Other medals for Team GB on Tuesday included a silver in the men’s team sprint in the velodrome and a bronze for 16-year-old Brown in skateboarding.
Colchester boxer Lewis Richardson was also sadly beaten by split decision in the 71kg semi-final and had to settle for bronze.
He took home Britain’s only boxing medal at the Olympics.
Meanwhile, in Tuesday’s final track event, the 200m final, Dina Asher-Smith and Daryl Neita both missed out on a medal.
Asher-Smith, distraught after missing out on a place in the 100m final, put in a strong performance but finished fourth in 22.22s and Neita fifth.
American Gabby Thomas took gold, 100m winner Julianne Alfred won silver and Brittany Brown came third.
Asher-Smith remained much more optimistic after the race, telling reporters “I’m really proud to have been able to hold my own with such a strong field.”
Elsewhere in the day, there was a heartbreaking blow for Andrea Spendrini-Siriex. The British diver was left in tears after finishing just sixth in the 10m final, despite performing well in the semi-finals.
The 19-year-old had previously won an Olympic bronze medal in synchro diving.