The Abbott World Marathon Majors Wheelchair Series XI concludes on Sunday in London, with Swiss pair Manuela Sch�r and Marcel Hug poised to be crowned champions.
Sch�r has enjoyed a stellar series, beginning with a win in the Virgin Money London Marathon in April and following up with victory at the BMW Berlin Marathon in September.
She was bested by American rivals Tatyana McFadden and Amanda McGrory in the Bank of America Chicago Marathon, but hit back in style in November when she stormed to victory in Central Park to take the TCS New York City Marathon crown.
When the series resumed in Tokyo in February 2018, Sch�r again proved too good for the rest of the field, cementing her sizeable lead at the top of the standings.
Defeat to McFadden in the freezing rain of Boston, where she withdrew before the end, has narrowed the 33-year-old's advantage, but not to the degree that she can be overhauled on Sunday.
McFadden has second place and $25,000 locked up, but there could be an interesting scrap for the third place in the Series, which this year comes with a $10,000 prize purse. McGrory holds the advantage on 45 points but can be usurped by Susannah Scaroni or Sandra Graf if either wins.
It's a similar story of Swiss success in the men's wheelchair division, where Marcel Hug has pulled clear of his competition as we had into the final round.
The Silver Bullet ended the debate in Boston on Monday when he pushed through the rain and away from South Africa's Ernst van Dyk to win his fourth straight Boston title.
That follows wins in Berlin, Chicago and New York City earlier in the Series that put him in a commanding position.
But the London crown eluded the man from Lucerne last April as Britain's David Weir outsprinted him on the Mall to take a seventh title in the UK capital, and Hug will be keen to end his title-winning season in style.
Beneath Hug, there is much to be settled, with the chances of the top three extending as far down the table as ninth place.
Van Dyk is currently second with 33 points, but poised below him are Kurt Fearnley (29), Weir (25) and Hiroyuki Yamamoto (25).
Johnboy Smith then separates the Tokyo 2018 champion from a clutch of otherJapanese athletes; Kota Hokinue, Tomoki Suzuki and Sho Watanabe.
With London producing famously tight finishes, the battle in those late miles will be one to watch.