Caeleb Dressel swims to share Michael Phelps' world record

Caeleb Dressel of the United States heralded a new era in world swimming when he equalled the great Michael Phelps' feat of seven golds at a single world championships as the 17th edition closed on Sunday.

The 20-year-old Dressel underlined his credentials as the world's fastest starter in breathtaking fashion at the Duna Arena when he broke away on the butterfly leg to give the US gold in the men's 4x100 metres medley relay.

Dressel had already won three individual golds and three relay titles in Budapest, and Sunday's addition allowed him to match his compatriot Phelps' tally from the 2007 championships in Melbourne.

He also helped the US to record their best-ever world championship haul, with 38 medals.

However the enormity of the Florida student's achievements had yet to fully sink in.

"I've never had it happen so I don't really know what to say," he told reporters. "I'm going to take a little break in Europe, go to Poland and Scotland and just enjoy myself.

"It was probably the most fun I've had in eight days. It was an absolute blast getting to do what I love."

Dressel's seven golds included three individual titles in the 50m, 100m freestyle and 100m butterfly, plus relay golds in the 4x100m freestyle, 4x100m mixed freestyle, 4x100m mixed medley and Sunday's 4x100m medley.

He became the first swimmer to claim three world golds in one session on Saturday by winning the 50m freestyle, 100m butterfly and mixed 4x100m freestyle titles in a jaw-dropping 98-minute spell.

"I'm very happy to be done, pretty tired," he said.

"Its been a good season, a good year, there are a lot more that goes into this than what people see in seven days."