LONDON –– The 35th Virgin London Marathon boasts perhaps the deepest fields in the history of big-city racing. The men’s field will feature five of the 10 fastest runners in history, including the top three among eight individuals who have completed the distance in under two hours and five minutes. On the women’s side, there are nine runners who have gone under 2:22 and 11 who have clocked in faster than 2:25. Here are some of the storylines you should follow while watching the clock.

Clash Of The Titans

Kenya’s Wilson Kipsang will defend his title against fellow Kenyan Dennis Kimetto, the man who took his world record last fall. Kimetto, who clocked 2:02:57 in September’s Berlin Marathon, will make his London Marathon debut. Kipsang, meanwhile, will be running the race for the fourth time having won in 2012 and in 2014, when he set the course record of 2:04:29. The two men train together at times in Iten, but have never faced off in a race.

READ MORE: Winning Trumps Time For Athletes At London Marathon

“London always has the best fields but with Dennis in the line-up this year it promises to be a bruising battle,” Kipsang told race organizers. “I certainly won’t give up my title belt without a fight, but let’s see who has the knock-out blow.”

Added Kimetto: “I broke Wilson’s world record in Berlin last year and now I want his London Marathon crown. I am relishing the chance to face my friend over the famous course. I know it won’t be easy but I am confident I can go the distance whatever he throws at me.”

Don’t Forget Us

While Kipsang vs. Kimetto might be the headliner, don’t sleep on the other runners in this field because any and all of them are capable of delivering an upset victory.

Emmanuel Mutai has the most experience in the field, with Sunday being his seventh London Marathon. The 2011 London champ ran 2:03:13 behind Kimetto in Berlin, which ranks as the second-fastest time in history.

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Eliud Kipchoge, the former world 5000m champion who brilliantly won the 2014 Chicago Marathon in 2:04:11 last October, has a 2:04:05 PB to his credit.

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Geoffrey Mutai, the two-time New York City Marathon champion and 2011 Boston Marathon champion, is over injury and eager to add a London title to his sterling resume.

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Stanley Biwott, the 2012 Paris Marathon champion and course-record-holder, will be looking to atone for a blow up here last year, when he took a sizable lead only to lose it to Kipsang in the final five miles.

Can The Queen Keep Her Crown?

Last spring, two-time world champion Edna Kiplagat raced to her first London victory in four tries, outlasting Florence Kiplagat (no relation) by just three seconds for the race’s closest finish in 17 years. Both women have dipped under 2:20 in the past, but Florence Kiplagat may be the runner entering with the hottest hand having just set the half marathon world record of 1:05:12 in Barcelona in February.

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The challengers to Edna Kiplagat’s title don’t end there. Priscah Jeptoo, the 2011 London Marathon champion, and Mary Keitany, the 2012 London winner and 2014 New York City Marathon champion, are also eager to return to the top of the podium. Jeptoo carries a personal-best of 2:20:14 while Keitany’s winning time of 2:18:37 here ranks as the second-fastest in history.

Kenya’s "fantastic four" won’t have the roads all to themselves, however. Ethiopia's Aselefech Mergia appears in form to do some real damage, having won the Dubai Marathon in January in 2:20:02, just 30 seconds off her PR. 

Hey, Hey Paula!

Paula Radcliffe, Great Britain’s most iconic female runner, will take a final bow from the sport on Sunday, when she runs what is believed to be her last competitive race in an event she has won three times. It was in the second of those three victories, in 2003, that Radcliffe set the world record of 2:15:25, a time no one has come within three minutes of since. Radcliffe will not run with the elites but in the mass field for the first time in her life.

READ MORE: No Regrets For Radcliffe Ahead of Final London Marathon

Throughout the latter stages of her career, Radcliffe has suffered from persistent foot and Achilles tendon injuries. Her most recent niggle nearly derailed her preparation for this final race.

”It's definitely looking a lot better now than even three weeks ago," she said of her Achilles. "It was going really well. I went out in Kenya in February, I thought I was being really careful and not getting carried away, but I probably did start thinking about what times I might be able to run. The trails are pretty rocky out there and I tweaked it. I didn't think it was that big a deal at first. It took about six weeks to settle down."

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Radcliffe, who added that she is “unfit and unprepared for a marathon, but hoping my body can remember once it gets out there how it's supposed to do it,” will receive the inaugural John Disley London Marathon Lifetime Achievement Award at the conclusion of the race.

Wheel-deal Showdowns

The men’s and women’s wheelchair races both figure to provide entertaining duals to the finish on The Mall.

Great Britain’s David Weir and Switzerland’s Marcel Hug appear set for a thrilling re-match in the men’s race. Last year, Hug edged Weir by a wheel-length, denying the Britton a record seventh title. This year, Hug enters with all of the momentum, having destroyed the field at the Boston Marathon on Monday by more than six minutes. Weir did not race in Boston.

While American Tatyana McFadden, the dominant figure in women’s wheelchair marathoning for more than two years, returns in search of a third straight title, there is real intrigue as to whether she will be able to keep alive her pursuit of a third sweep of the majors.

McFadden won her third straight Boston Marathon title on Monday, but needed to grind it out under wet and cold conditions. In March, McFadden was beaten handily at the NYC Half by Switzerland’s Manuela Schaar. Schaar did not race in Boston and comes into this race, which is doubling as the IPC World Championships, fresh.