Farah and Rupp face African challenge in Chicago

Ethiopians Mosinet Geremew and Birhanu Legese and Kenyans Dickson Chumba, Abel Kirui and Kenneth Kipkemoi all have run faster than British marathon record holder Farah and reigning champion Rupp with Kirui and Chumba former Chicago winners.

Kenyan world championship gold medallist Geoffrey Kirui is also a major threat.

"You’ve got guys who’ve run 2:04," Farah told Runner's World. "There are seven or eight good guys. I don’t even know who to think could win that race."

But the intriguing story of two former partners chasing the same goal makes for high theatre.

U.S. Olympic marathon bronze medallist Rupp and Farah, four times an Olympic gold medallist on the track, trained together in Oregon for six years before Farah returned to Britain in 2017.

Now they face off on the roads with American Rupp still coached by Alberto Salazar and Farah, now 35, running his first U.S. marathon under the guidance of Gary Lough, the husband and former coach of women's world marathon record holder Paula Radcliffe.

“It’s part of making the race exciting -- it’s what people want to see," Farah said when asked about the rivalry.

"Like, when you go to watch boxing you want to see the best boxers fight each other. There’s a lot of talk, you know? That’s how athletics is and why all the fans support us. Only the best man will do it on the day. It’s nice to give the people who’ve seen us throughout our careers something to watch.”

Both profess to be in top shape.

Farah, who claimed the British record with his 2:06:21 for third in April's London Marathon, hopes to eclipse Norwegian Sondre Nordstad Moen's European record of 2:05:48.

"For me satisfaction will be to run a personal best," he said.

Rupp, who clocked 2:06:07 at Prague in May, also wants to go faster.

"This is probably the best situation I’ve ever been in to run fast,” said the 32-year-old American, who won last year's race in 2:09:20. The U.S. record is 2:05:38.

Kenyans Brigid Kosgei, the 2017 runner-up, and Florence Kiplagat, a two-time Chicago winner, will likely headline the women's field along with Ethiopians Roza Dereje and Birhane Dibaba. All have run 2:20 or better.

Wet weather, however, could affect racing. There is a 50 percent chance of showers. (Reporting by Gene Cherry in Salvo, North Carolina Editing by Toby Davis)