The Americans finished with ten medals, including three golds - their best tally in 16 years.

Italy finished one place ahead of the US at the top of the medals table as the Championships came to an end at the Plovdiv Rowing Lake, also earning three golds but having four, as opposed to three, silvers in a total of eight.

Last year in Florida the previously all-conquering US women's eight finished one place outside the medals in a final won by Romania, with Canada and New Zealand taking silver and bronze.

In Plovdiv they returned to the top spot after a tight race in which Canada took another silver and Australia earned bronze.

"We just had so much belief and so much trust, and that's what we did all the way down the course," said the cox, Katelin Guregian.

"If anyone had let go of their belief or their trust, it would have been over.

"I think that's what carried us through.

"The conditions were crazy out there - headwind, tailwind, crosswind, just coming from every direction.

"We believe in each other with our whole hearts, and we just followed that down the course.

"It feels amazing to have won that race."

The US further demonstrated its women's sweep rowing dominance by winning the women's four - the new Olympic boat class.

Italy's distinctions included their first gold in the men's quadruple sculls since 1998 after a race in which Lithuania's defending champions were outside the podium as Australia and Ukraine took silver and bronze respectively.

Ireland had its most successful World Championships ever, picking up two gold medals and their first golds in Olympic boat classes.

The first had come in the lightweight men's double sculls thanks to the O'Donovan brothers, Olympic silver medallists Paul and Gary.

The second gold came in the blue riband event of the women's single sculls, where Sanita Puspure beat the reigning world champion, Jeannine Gmelin of Switzerland, to the line.

The 36-year-old Puspure, born in Latvia, moved to Ireland in 2006 and has competed for them since 2010.

Gmelin took silver and bronze went to Austria's Magdalena Lobnig.

In the highly anticipated men's single sculls the reigning European champion, Kjetil Borch of Norway, led from start to finish to take his first ever world title.

Borch pushed the world champion, Ondrej Synek of the Czech Republic, into second with Lithuania's Mindaugas Griskonis sprinting through to a bronze.

In the Para-rowing boat classes new world best times were set with the most impressive being in the PR1 men's and women's single sculls.

In winning his fifth consecutive PR1 men's title, Erik Horrie of Australia set a new world best time of 9min 16.90sec after being pushed all the way to the line by Ukraine's Roman Polianskyi.

"That was a race," said Horrie after cutting nine seconds from the time he set earlier in the Championships.

"Painful and very fast.

"Roman is a very good rower, we always knew it would be a sprint finish.

"I take my hat off to him."

The defending champion in the women's single, Birgit Skarstein of Norway, dominated her race to better the previous world best time by 11 seconds, clocking 10:13.63.

The defending German men's eight closed the Championships by successfully defending their title in a tightly fought final in which Australia took silver and Britain bronze.