Sunday, 22 December 2019:

CATE CAMPBELL at the Optus Aquatic Centre in Gold Coast, Australia.

A rare loss for Australia's Cate Campbell has helped Energy Standard upstage London Roar and claim the inaugural International Swimming League's grand final in Las Vegas.

In a bittersweet end to a memorable year, Roar star Campbell was upset by Sweden's Sarah Sjostrom in the final 50m freestyle event as Energy Standard stormed home in the short-course showcase on Sunday (AEDT).

The 28-strong Europe-based outfit Energy Standard - featuring sole Australian Emily Seebohm - snatched the ISL trophy and split $A145,000 prize money by topping the standings on 453.5 points - just 9.5 ahead of London (444pts).

The two-day grand final also featured US teams Cali Condors (415.5pts) and LA Current (318pts).

It was a thrilling finish to the maiden ISL which will expand to 10 teams next season, with Tokyo and Toronto franchises unveiled on Sunday.

The stage was set for Campbell to cap a dream year when London led Energy Standard by 23 points with only two events remaining - the women's and men's 50m freestyle skins.

However, Sjostrom showed why she looms as one of Campbell's greatest Tokyo Olympics threats when she mowed down the Australian in the women's skins final to give Energy Standard momentum for an upset.

Energy Standard completed the boilover in the men's final of the skins - an elimination format which whittles down an eight-strong field until just two battle it out in a third and final round.

Condors' American superstar Caeleb Dressel won the men's skins final but French giant Florent Manaudou registered enough points for Energy Standard to pip London for overall ISL honours.

Dressel was named MVP of the Las Vegas grand final after also clocking a US Open record 45.22 seconds to pip Roar's Olympic champion Kyle Chalmers of Australia (45.55) in the 100m freestyle final.

Sjostrom collected $A72,500 prizemoney as the inaugural season's overall MVP with 243.5 points ahead of Dressel (240) and Australia's Roar star Emma McKeon (192).

Campbell fell short in the 100m freestyle ISL final on Sunday, finishing third with McKeon claiming a shock win over Sjostrom.

Campbell now draws the curtain on the biggest 12-month program the veteran has ever attempted.

In what looms as perfect preparation for Tokyo, Campbell, 27, helped London qualify for the ISL grand final after dominating the seven-leg World Cup series where she picked up almost $500,000 in prize money.

Campbell then emerged as one of the stars of the inaugural six-leg ISL, the brainchild of Ukrainian billionaire Konstantin Grigorishin, which featured more than 100 Olympians.

Next season will be held from September 2020 to April 2021.

AAP