Great Britain's Dina Asher-Smith praised her teammates after a historic hat-trick at the World Championships.
The 23-year-old became the first British athlete to win three medals at the same World Championships following 4x100m relay silver on Saturday.
Having already claimed 200m gold and 100m silver in Doha, she linked up with Asha Philip, Ashleigh Nelson and Daryll Neita as the quartet finished second behind Jamaica in 41.85 seconds.
The United States were third while the men's 4x100m squad then added another silver, unable to defend the title won in London two years ago.
The women's squad were forced into a last-minute change after Philip replaced Imani Lansiquot, who pulled out with a thigh injury.
Asher-Smith was oblivious to her achievement but hailed the squad.
She said: "I did not know that. It feels great but in all honesty that wouldn't even be a conceivable idea if not for the teamwork.
"The relay is a team event. You can't do that on your own, so thank you ladies.
"We hope Imani is OK because we made a last-second change.
"We made the decision to run a different team and that was just before the call room. That's testament to all of our experience over the past few years as a relay squad.
"We can go out there without directly doing the changeovers in the warm-up area and almost run a personal best and get a world silver medal. Maybe a cycle or two ago it would have been an inconceivable idea."
GB captain Kilty said: "It felt incredible. What more could we ask? It took the second-fastest time in history to beat us. That was the best team America have ever assembled.
"Zharnel, what a warrior. He pulled his hamstring coming into the zone so we had to slow it down that change and break.
"He went through a pulled hamstring to deliver me that baton. We're so proud of each other."
Earlier, Shara Proctor and Abigail Irozuru qualified for Sunday's long jump final, but Jazmin Sawyers missed out.
Cindy Ofili came through the 100m hurdles heats, finishing third in 12.97s.
In the women's 4x400m relay heats Zoey Clark, Jodie Williams, Jessica Turner and Laviai Nielsen reached Sunday's final in 3:24.99.
The men's team of Cameron Chambers, Rabah Yousif, Martyn Rooney and Lee Thompson scraped into the final after Botswana were disqualified.