The showpiece, featuring eight nations in a rapid format designed to attract fresh audiences to track and field, was expected to suffer from the non-availability of many leading lights with South African middle-distance star Caster Semenya joining the no-shows on the eve of the event.
However, with a 30,000-strong crowd attracted to the 2012 Olympic stadium despite the competing priorities of football's World Cup and Wimbledon tennis, initial feedback from organisers and athletes suggests it is a format which has the potential to continue.
Even with a lengthy list of absentees, the Americans claimed the maximum eight points available by winning five events.
Jeron Robinson landed victory in the men's high jump with a clearance of 2.30m, Clayton Murphy took the men's 800m and Ashley Henderson edged out Olympic champion Elaine Thompson to win the women's 100m in 11.07 seconds, before the USA won both the women's 4x400 and men's 4x100m relays.
"It was fun to get back to the team competition because I sort of miss that from college," Murphy said. "To have so many different sport events happening and still get this big of a crowd is awesome."
His efforts helped propel the Americans into top spot in the standings on 109 points with France behind on 85, Poland and Jamaica level on 77 with hosts Britain and Northern Ireland in fifth place on 74.
Poland made the strongest possible start with three early victories, with two-time Olympic champion Anita Wlodarczyk throwing a world lead of 78.74 metres to win the women's hammer ahead of Rio 2016 bronze medallist, Sophie Hitchon of Britain.
"It is the best result for me this year," Wlodarczyk declared. "I have great memories in the Olympic Stadium in 2012 and last year and here I am winning again."
There were two home wins with British team captain Lorraine Ugen leaping 6.86m for first place in the long jump and Holly Bradshaw victorious in the pole vault.
Jamaica's Janieve Russell was an impressive victor in the 400m hurdles but her compatriot Ronald Levy was held off by Pascal Martinot-Lagarde in the 110m hurdles, with the French champion sensing he is reaching his best form ahead of next month's European Championships in Berlin.
"I can be in better shape by Berlin," he said after running 13.22 seconds, his quickest time of 2018.
"I saw some elements at the end of the race that I can improve but I got eight points and first place here and that was perfect."
Sunday's action includes the men's 100 metres where American Kendal Williams, who has run 9.99 seconds this season, will start as favourite.
While South Africa's Luvo Manyonga, who claimed the world title in the London Stadium eleven months ago, heads the rankings in the men's long jump.
The team with the most points at the conclusion of the Athletics World Cup will share a prize fund of $450,000 (£342,000).AFP