Kenya's men and women both claimed new world records in the 4x1500m at the IAAF World Relays in the Bahamas.
The men's time of 14 minutes 22.22 seconds bettered by 14secs a 2009 Kenyan record, while the women beat the previous mark by over half a minute.
Yohan Blake led Jamaica to victory in the 4x100m relay, with Great Britain taking the bronze medal.
GB's women picked up a silver in the 4x200m in a new national record, but the women's 4x400m team disappointed.
The quartet finished seventh at the inaugural championships and 400m world champion Christine Ohuruogu, who came into the team for the final, admitted: "That was my first opener and it wasn't a very good run.
"There is nothing to worry about. It was a hard race and we've had a good few days of work together."
GB's men's 4x400m fared better in finishing fourth, with Nigel Levine running the third leg with only one shoe.
Britain's first medal at the event in Nassau came when the 4x200m women's team of Desiree Henry, Anyika Onuora, Bianca Williams and Asha Philip clocked a time of 1:29.61.
"We just wanted to put a marker down for Commonwealths and Europeans. The competition is going to be hot to get in the team," said Onuora.
Shortly after the women's triumph, the men's 4x100m team of Richard Kilty, Harry Aikines-Aryeetey, James Ellington and Danny Talbot finished third in 38.19 seconds.
The Kenya men's record-breaking team included Asbel Kiprop, the 1500m world champion.
Despite the absence of six-time Olympic champion Usain Bolt through injury, Jamaica men's sprint quartet - led by Blake - broke a 20-year-old 4x200m world record on Saturday.