Olympic champion Adam Peaty helped London Roar to a stunning 217-point victory in their season-opening International Swimming League (ISL) match in Budapest.
Peaty, who was second in both the 50m and 200m breaststroke events on day one, won the 100m race and world champion team-mate Duncan Scott took the 200m freestyle title.
"The aim is to get faster throughout the meet and I haven't raced since the start of the year so it's great to come back with a win," he told BBC Sport.
Former Olympic champion Ranomi Kromowidjojo of the Netherlands claimed the Most Valuable Player award with wins in the 50m freestyle and butterfly for Team Iron, who finished second.
Their captain - three time Olympic champion Katinka Hosszu - returned from a difficult opening day with strong performances and victories in the 200m butterfly and 400m individual medley events.
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Although the first season of the ISL took place in fixtures across Europe and the USA before a grand finale in Las Vegas, due to the coronavirus, the entire second season of the ISL is being held in a Budapest bio-bubble.
US franchise Cali Condors defeated last season's winners Energy Standard the opening match on Saturday, but 2019 runners up London Roar proved they will again be among the main contenders.
Backstrokers Maria Kameneva (Russia) and Christian Diener (Germany) won the mega-point-scoring head-to-head 'SKINS' races to close out London Roar's commanding victory.
In addition to Peaty and Scott, other Britons to impress for the UK franchise included Kathleen Dawson (second in 100m backstroke), Anna Hopkin (second in 100m freestyle), Emily Large (third in 200m butterfly) and Aimee Willmott (third in 400m individual medley).
"It's been amazing, a great performance and probably a little better than we would have expected," London Roar general manager Rob Woodhouse told BBC Sport. "We're also giving a lot of swimmers opportunities in events they don't usually swim, so that sets us up well for five weeks ahead."
The team were missing James Guy, Freya Anderson, Holly Hibbot and Tom Dean as the foursome were forced to quarantine in the UK after coming into contact with someone in Bath who tested positive for Covid-19.
None of the athletes tested positive themselves and will be available for London Roar's next fixture on 30-31 October - against DC Trident, LA Current and Tokyo Frog Kings.
London Roar 610.5
Team Iron 393.5
DC Trident 351
Aqua Centurions 339
You can follow live coverage of each of London Roar's four qualifying matches as well as the ISL semi-finals and final in Budapest across the BBC Sport website, app and BBC iPlayer.