Dame Flora Duffy will be aiming to upset the odds when she takes to the start line of the Professional Triathletes Organisation US Open in Dallas tomorrow.

The Olympic Games, Commonwealth Games and world champion is set to make her debut in the event, the second race of the PTO Tour, which will be competed over a 100-kilometre course consisting of a two kilometre swim, 80km bike 18km run.

While the course is slightly shorter than the 70.3 distance and so may favour the Olympic distance athletes, Duffy, who enjoyed an encouraging debut competing in the Collins Cup triathlon series last month, is by no means a clear favourite among a stellar field of middle of distance specialists.

Her biggest challenge for the top step of the podium will come in the form of Ashleigh Gentle, who ran down Paula Findlay to claim victory in the opening race of the Tour in Edmonton.

While, Chelsea Sodaro, third last time out, will be absent in Dallas, the likes of Holly Lawrence and Ellie Salthouse, sixth and eighth respectively in Edmonton, will be eyeing a podium place along with Lucy Charles-Barclay, one of four late additions to the race alongside Duffy.

The British athlete has fully recovered from lingering injuries and will be full of confidence after her victory at the World Triathlon’s Long Distance World Championships last month in Samorin, Slovakia.

Equally as threatening is Olympic mixed relay silver medal-winner and World 70.3 World Championship bronze medal-winner Taylor Knibb, while the final late addition Kat Matthews, of Great Britain, will also be considered a contender.

Matthews earned a silver at the recent Ironman World Championship in St George, will she also became the first woman to finish a full distance triathlon in under eight hours, stopping the clock in 7hr 31min 54sec, to make history at the Dekra Lausitzring in Senftenberg, Germany.

The men’s race, taking place a day later, is also expected to hotly contested with PTO’s world No 3 Magnus Ditlev and No 4 ranked Lionel Sanders heading the field in the absence of Kristian Blummenfelt and Gustav Iden.

Others who will be expected to challenge include the likes of two-time Olympic champion Alistair Brownlee, Sam Long, a silver medal winner at Ironman 70.3 World Championship and Aaron Royle, third last time out in Edmonton.

As triathlon’s first grand-slam series, the PTO Tour is a big draw for the worlds best triathletes with a $1 million purse with $100,000 each going to the men's and women’s champions, $70,000 to the runners-up and $50,000 to the third-place finishers. Even those who finish 40th or later take home $2,000.