Zhang Yufei targets China's first gold in Paris pool as doping clouds loom

Zhang, gold medallist in the event at the Tokyo Games three years ago, clocked two minutes, 6.55 seconds to go top of the time charts ahead of the United States' Regan Smith and Australian Abbey Connor in a low key session at La Defense Arena.

The 'Butterfly Queen' as Zhang is known also posted the best time in the 100m butterfly heats on Saturday but came up short in the final, taking bronze behind Americans Torri Huske and Gretchen Walsh.

The third place brought questions about a doping scandal involving Chinese swimmers that has escalated in Paris as reports of more positive tests surfaced in a New York Times report on Tuesday.

The Times and German broadcaster ARD reported in April that Zhang was among 23 Chinese swimmers that were allowed to compete in the Tokyo Olympics despite testing positive earlier in the year for heart medication trimetazidine, a drug banned by the World Anti-Doping Agency (WADA).

WADA has not named any of the swimmers.

A Chinese Foreign Ministry spokesperson said this month it was a "non-existent case that the US keeps selling" with the aim of "degrading" Chinese athletes and "obstructing their participation in the Paris Olympics".

Zhang had said after the 100m butterfly she was worried about how her fellow swimmers saw her and she will no doubt have similar worries if she can get to the wall first in Thursday's final.

Defending her gold will not be easy with Canadian wunderkind Summer McIntosh targeting her third Paris medal and second gold, the first coming with a dominating swim in the women's 400m individual medley.

The 17-year-old's haul also includes a silver in the 400m freestyle.

"Trying to feel as fresh as possible and kind of treat it like a new week," said McIntosh, who posted the sixth best time in the heats, easily qualifying for Wednesday evening's semi-finals.

"This morning I was just trying to make semis and conserve as much energy as possible heading into tomorrow's final.

"I think there's been a lot of unpredictable swims overall so far. When I say unpredictable, I mean anything can happen in a final. Anyone can win.

"I just think any Games is unpredictable when it comes to swims."