Her coach Mason Rebarchek said Shereen, who is making her debut in the meet on a wild card, was “fit, fast and ready to go”.

“It’s easy to get distracted in a new environment but she has done a good job staying focused, ” Rebarchek told FMT after a workout at Hayward Field in Eugene, Oregon, on Saturday morning.

“She seems her normal self, which is a great thing,” said Rebarchek who has been Shereen’s coach since 2019.

He said he was confident that Shereen would run a fast race as her speed and explosiveness were at a whole new level.

Rebarchek said it would be a great achievement for her if she bettered the 29-year-old Malaysian 400m record of 52.56 seconds.

The mark belongs to the late Rabia Abdul Salam while Shereen’s Olympian mother, Josephine Mary, is the second fastest over the event at 52.65s.

Rebarchek had guided Shereen to her personal best of 52.68s to win the 400m gold at the US National Collegiate Athletic Association (NCAA) division II track and field championships in May.

The Oregon22 showcase is the biggest stage yet for Shereen and she will run in lane two in heat six of the women’s 400m heats.

Shereen, of Winona State University in Minnesota, who is ranked 229 among 400m runners in the world, is up against seasoned racers who have featured in top meets such as the Diamond League.

The favourites to win heat six are Candice McLeod of Jamaica, who is sixth in the world ranking (WR) and has a personal best (PB) of 49.51s, and ninth-ranked Anna Kielbasinska of Poland whose best is 50.28s.

The other athletes are Lada Vondrova (Czech Republic, PB 51.13s, WR 27), Tiffani Marinho (Brazil, PB 51.51s, WR 36), Rosie Elliot (New Zealand, PB 52.59s, WR 49), Victoria Ohuruogu (Great Britain, PB 51.05s, WR 55) and Natasha McDonald (Canada, PB 50.91s, WR 62).

The first three from each heat and the six fastest times will qualify for the semi-finals.