Cape Town - South Africa's Chad le Clos started his title defence with a silver medal on the opening day of the first leg of the FINA World Swimming Cup in Kazan on Friday.
In the men's 100m butterfly, the 26-year-old came in tied for second along with Russia's Igor Kuimov - touching the wall simultaneously at 52.00 seconds.
America's Michael Andrew edged the duo as he won the race in a time of 51.96.
South African compatriot Ryan Coetzee, who won bronze at the Commonwealth Games this year, missed out on a podium position as he finished fourth (52.10).
Le Clos made history last year when he became the first man to win four World Cup Series titles - winning in 2011, 2013, 2014 and 2017.
The men's and women's series winners take home $150 000 each with an additional boost for the each overall cluster winner, who collects $50 000.
The opening leg of the Swimming World Cup in Kazan continues on Saturday and Sunday.