PARIS: A doping row involving Chinese athletes may prove a tinderbox at the Olympic swimming meet where the United States face the biggest challenge to their reign in decades from Saturday.
Some of the world's best in the sport have criticised anti-doping authorities and raised concerns about the competition's integrity following revelations in April that 23 Chinese swimmers were allowed to compete at the Tokyo Games despite testing positive for the banned heart medication trimetazidine (TMZ).
The World Anti-Doping Agency accepted the findings of a Chinese investigation that the test results were due to contamination from a hotel kitchen the team were staying at.
An independent investigation backed WADA's handling of the case in its findings this month – but for a number of China's rivals, questions remain.
American seven-times Olympic champion Caeleb Dressel put it bluntly when asked on Thursday if he felt confident of a level playing field.
"No. I don't," he said.
"I don't really think they've given us enough evidence to support them with how this case was handled."
China's swim team at Paris includes 11 of the 23 athletes reported to have tested positive by the New York Times and German broadcaster ARD in April.
None of the 11 athletes nor the Chinese Swimming Association have commented publicly on the matter.
Their presence at Paris's La Defense Arena could prove a flashpoint, though, particularly if medals are involved.
Australia's 200 metres breaststroke Olympic champion Zac Stubblety-Cook said he would decide whether to make an anti-doping protest after racing China's world record holder Qin Haiyang. Other swimmers could take a stand, he added.
The sport may prevail over the acrimony, though, at a temporary pool dropped into a rugby stadium that can pack in 15,000 spectators.
Day one will start with a bang when the U.S. and Australia clash in events that could set the tone in the medals race.
Three years after their epic tussle at Tokyo, Australia's Olympic champion Ariarne Titmus and American great Katie Ledecky will have a re-match for the 400 metres freestyle gold.
With Canadian wunderkind Summer McIntosh, a former world record holder also in the mix, the 400 could be Paris's candidate for "race of the century."
Though Australia have not topped the Olympic swimming medal count since the 1956 Melbourne Games, they finished a close second to the U.S. at Tokyo and will hope to go one better.
The U.S., meanwhile, have not been off the top of the medal table since coming second to East Germany in 1988.
The performance of the team's Tokyo captains Ledecky and Dressel may be crucial for U.S. hopes of extending their reign.
Already regarded the greatest women's swimmer with six individual Olympic gold medals, Ledecky will defend her 800m and 1,500m freestyle crowns later in the meet.
Dressel will defend his 50m freestyle and 100m butterfly titles and could surpass Mark Spitz's nine gold medals to be second on the all-time Olympic list behind Michael Phelps.
Australia will rely heavily on Titmus, also the 200m freestyle champion, and a stable of brilliant women to challenge the Americans.
Kaylee McKeown will bid to become the first woman to do the backstroke "double-double" by successfully defending her 100 and 200m titles from Tokyo.
Her battles with American Regan Smith, who recently snatched the Australian's 100m world record at U.S. trials, should thrill.
Most of the crowd will gun for Leon Marchand, the 22-year-old Frenchman prepared by Phelps's former coach Bob Bowman.
Since Tokyo, Marchand has ruled the 200 and 400m individual medley and could emerge with four individual golds.
British world record holder Adam Peaty will bid for a third straight 100m breaststroke gold and join Phelps, the only man to successfully defend a swimming title twice or more.
But Qin, the Chinese world champion last year, stands in Peaty's way.
Dressel will not defend his 100m freestyle title but it promises to be a cracking race without him.
Australia's Kyle Chalmers, the 2016 Olympic champion and Tokyo runner-up, will take on China's 19-year-old world record holder Pan Zhanle and the Romanian rocket David Popovici in the blue riband 100m freestyle sprint. - Reuters