NAIROBI, Aug. 29 (Xinhua) -- London Marathon champion Brigid Kosgei will go against compatriot Betsy Saina to challenge for medals at the Chicago Marathon on Oct. 13.

They will face a strong challenge from the Americans, though the Kenyans stand out stronger owing to their past performances.

Kosgei, who is coming off a 2:18:20 personal best run in London, has opted out of the Kenya team to the World Championships to defend her title in Chicago, where she is the obviously favorite.

"Chicago is the next stop for me," said Kosgei on Thursday. "It is a fast and good course that inspires athletes to run fast time. But it will enforce my resolve to make the Olympic team next year."

Kosgei won the Chicago race last year clocking 2:18:35 and will want to run faster and see if she can improve on her best time from London attained in April.

But she will be cautious of the never-say-die attitude that compatriot Saina carries.

There is also the potential threat from Jordan Hasay, who ran 2:20:57 in Chicago two years ago and just finished third in Boston. She has shown that she is in great shape.

But the two other sub-2:24 performers are hardly consistent.

Saina may have failed to finish the race in her first two marathons before winning 2018 Paris in 2:22:56. Since then, she's run 2:24:35 for eighth spot in Frankfurt and 2:30:32 for tenth in Boston.

Critics say the women's field in Chicago is one of the weakest ever assembled at a World Marathon Major.

Though there are two Kenyans entered - and no Ethiopians - and while that's not the only measure of quality, the personal bests in this field won't blow anyone away.

The return of champion Kosgei will give the race and the organizers some credence of another potential battle for fast time.

Kosgei is the top female marathoner in the world right now after wins in Chicago and London. But Jordan Hasay is the only other woman in the field who has run faster than 2:22:56 - and one of only four women in the field to have broken 2:25.