Chicago is the major American marathon with the flat and fast course, where world-class runners go to run personal bests and chase records in the fall. Here’s what to watch for in Sunday's race. On race day, follow our live coverage here.

1. Who’s the Men's Favorite: Kenenisa Bekele or Eliud Kipchoge?

The two favorites are track veterans who are relatively new to the marathon. Their rivalry dates to 2003, when Kipchoge of Kenya was the surprise winner over Ethiopia's Bekele in the World Championships 5000-meter final. Bekele, the 5K and 10K world record holder and three-time Olympic champion, has usually come out on top. The two had earlier talked about working together in Chicago, but Kipchoge has since said he'll run his own race.

Kipchoge’s 2:05:00 triumph in Rotterdam in April, with a furious finish and a victory margin of more than a minute, may mean more in handicapping Chicago than does his second place 2:04:05 in Berlin in 2013, when he couldn’t keep up with Wilson Kipsang’s world record (since broken) of 2:03:23. Bekele won April's Paris Marathon, his debut, in 2:05:04 in what looked like a controlled effort. He’ll run an intelligent race, and should win.

2. Can Anyone Beat Bekele and Kipchoge?

Not unless the pair get locked into a duel at such a suicidal pace that they both blow up. Bernard Koech has a 2:04:53 PR, but that was a fifth place effort at the speedway that is the Dubai Marathon. He’s most likely in the race because he’s Kipchoge’s training partner.

Ethiopia’s Tadese Tola's 2:04:49 PR was another non-winner (third place) in Dubai. He was the 2013 World Championships bronze medalist, however. Bet on him for third in Chicago on Sunday. Sammy Kitwara was a distant third in Chicago last year, and is likely to be similarly behind the two headliners on Sunday.

3. Who's the Women's Favorite: Rita Jeptoo or Florence Kiplagat?

Jeptoo, 33, has won two straight in Boston, including a course record 2:18:57 this April, and Chicago last October. Kiplagat, 27, the world half marathon record holder (1:05:12) and a two-time Berlin Marathon champ with a best time of 2:19:44, is ambitious and confident (which can be either good or bad), and has better times at shorter distances. But Jeptoo’s steady and patient. There’s no real reason to think her mastery will end this weekend.

Beyond the top two, there’s Birhane Aderu, the runner-up in Tokyo in February in 2:22:30. She defeated Jeptoo by three seconds in the Rock ’n’ Roll San Jose Half Marathon on June 1, but that means little in October. Mare Dibaba’s personal best of 2:19:52 is another one of those non-winning Dubai showings, a third in 2012. Her 2:21:36 to win in Xiamen, China earlier this year may be more impressive. But she’s not in the class of Jeptoo or Kiplagat.

4. What Records Might Fall?

Don’t expect any world records. As race director Carey Pinkowski told the Chicago Tribune, none of the women runners talk about breaking Paula Radcliffe’s world record of 2:15:25. She's had the Chicago course record of 2:17:18 for 12 years, and it will probably remain untouched on Sunday. Kiplagat has said she's aiming for 2:18. Jeptoo is unlikely to run two and a half minutes faster than her 2:19:57 of last year. Expect a winning women’s time of around 2:19:30.

The Chicago men’s record, 2:03:45, was established last October by Dennis Kimetto, who set the world record of 2:02:57 in Berlin last month. Bekele should improve on his 2:05:04, but not by that much, and if Eliud Kipchoge were a sub-2:04 man, we should have seen that by now. Look for a winning time of around 2:04:30.

5. How Will the Americans Do?

Americans are unlikely to be a factor in either race. Bobby Curtis has the fastest PR, 2:13:24; his 10,000-meter best of 27:24 suggests he’s capable of running faster. Christo Landry, who has won U.S. road titles at shorter distances this year, can certainly improve on his best of 2:14:44. A couple of foreign elites are sure to blow up after striving to stay with the leaders, so Curtis or Landry or both could crack the top ten.

On the women’s side, Amy Hastings insists she’s returned to the form that made her a 2:27:03 marathoner in her 2011 debut. A marathon debut by 2012 Olympian Lisa Uhl might have been more eagerly anticipated a couple of years ago; her race results of late have been meager. Clara Santucci, who ran a 2:29:54 debut in Boston in 2011 and won the Pittsburgh Marathon in May, could use Chicago to show she’s ready to supplant some 30-somethings and make the 2016 Olympic team. Chicago’s women’s field isn’t as deep as the men’s, so a fifth place finish by Hastings or Santucci is not unlikely.

Related:

Kenenisa Bekele, Eliud Kipchoge to Team Up at Chicago Marathon

Amy Hastings Looks to Rekindle Marathon Magic in Chicago

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io