The Energy Standard team, ISL champions in 2019, ended on 262.5 points, 27.5 clear of Aqua Centurions in second at the Piscina Felice Scandone.

Toronto Titans looked set to end the day in second but they were forced to withdraw from the men’s 4x100 metres medley relay.

SwimSwam reported the Canadian outfit were unable to field a team in the race because of a slight injury to former 100m freestyle world champion Brent Hayden.

The Titans pulling out of the relay meant they were dealt an eight-point penalty, allowing the Centurions to ensure they will go into the second day as the closest challengers to Standard.

Chad le Clos of South Africa, the Olympic gold medallist and four-times world champion who failed to win a medal at Tokyo 2020, earned 10 points for his team with victory in the men's 100m butterfly.

Le Clos touched the wall in 49.27sec to beat Titans' Marius Kusch and Zach Harting of the DC Trident team.

Evgeny Rylov, who won two gold medals representing the Russian Olympic Committee at Tokyo 2020, also delivered maximum points for Standard.

The Russian claimed victory in the men's 200m backstroke - which he took gold in at the Olympics in the Japanese capital - after clocking a time of 1min 49.61sec.

Sweden's Sarah Sjöström was another winner for Standard as she triumphed in the women's 50m freestyle in 23.50, while there was a first ISL victory for her team mate Ben Proud of Britain, who won the men's equivalent in 21.15.

The match is scheduled to continue tomorrow.