LONDON, England — Defending 100m hurdles champion Danielle Williams leads six other Jamaicans into action for the first time today here at the Olympic Stadium starting at 4:10 am Jamaican time.

Williams will be joined by Megan Simmonds, Yanique Thompson and Rushelle Burton in the 100m hurdles, while Jamaica will have three ladies in the discus event with Kellion Knibb, Tarasue Barnett and Shadae Lawrence.

Williams, who stunned the world at the World Championships in Beijing, China, will be the first in action in heat one. She is back in the form of her life registering a personal best of 12.56 seconds to win the Jamaican title and finished third at the IAAF Diamond League meeting in Monaco, just 0.07 behind world record holder Kendra Harrison.

Williams, or “Ants”, will have most to fear from Norway’s Isabelle Pedersen (12.75), Germany’s Pamela Dutkiewicz (12.61) and Brazil’s Fabiana Moraes (12.84).

The diminutive Simmonds, who has a seasonal and personal best of 12.63, will line up in heat two with Nia Ali (12.48) of the US and Great Britain’s Tiffany Porter (12.51).

World Youth champion from 2013, Thompson is in heat three with Kendra Harrison (12.20) and Devynne Charlton of The Bahamas, who has a personal best of 12.74.

Jamaica’s fourth entrant Burton is in a tough heat alongside US 2008 Olympic champion Dawn Harper Nelson and Sally Pearson of Australia.

The first four in each heat and the next four fastest advance to the semi-finals.

Meanwhile, three women are down for the discus in national champion and record holder Knibb and Barnett who will compete in Group A, while Lawrence will throw from Group B.

Knibb, who broke the national record twice this year, has a personal best of 62.73m, and Barnett, who has a personal best throw of 61.66m, will have to contend with Sandra Perkovic of Croatia with 71.41 and Denia Caballero of Cuba with 70.65m. There is also Anna Ruh of Germany with 66.14m

In Group B, Lawrence, who has a best of 62.59m, has most to fear from Cuba’s Yiame Perez, who has a best of 69.19m and Dani Steven of Australia with 67.99.

The qualifying mark is 62.50 to secure a spot in the final or the best 12 performers.