Kenyan marathoner Kelvin Kiptum won the 2023 London Marathon on Sunday, April 23. His finishing time of 2:01:25 shattered Eliud Kipchoge’s course record from London by nearly a minute while also falling just 16 seconds short of breaking Kipchoge’s world record mark of 2:01:09 set at the Berlin Marathon in September 2022.

The 23-year-old Kiptum was running his second competitive marathon. In his marathon debut in Valencia, Spain in 2022, Kiptum ran 2:01:53, which made him only the third man in history to run under 2:02, joining Kipchoge, who is widely considered the greatest marathon runner of all time, and Kenenisa Bekele, the multiple Olympic and World Championships gold medalist who is generally considered the greatest distance runner of all time.

Even more impressively, Kiptum’s historic time in London came from his running a substantial negative split wherein he ran the second half of the race in under 60 minutes, the fastest half-marathon split in known marathon history. While the current world record forthe half marathon stands at 57:31 set by Jacob Kiplimo of Uganda in 2021, Kitpum’s second half split of 59:45 harkens back to Kenyan runner Moses Tanui’s then-world record of 59:47 from Milan, Italy in 1993. Tanui’s sub-60 minute clocking was the first time in history anyone had broken the hour for the half marathon. Kiptum ran two seconds faster in his second half of his full marathon on the streets of London on Sunday.

In the women’s race, Dutch athlete Sifan Hassan overcame leg cramps that forced her to stop to stretch to win the race in 2:18:33. Rain dampened the possibility of the historically strong women’s field from clocking times commensurate to expectations as multiple runners in the field have personal bests in the 2:17s. After a solid first half split that saw Hassan fall off the pace, the leaders slowed down, allowing Hassan to regain contact. In the final miles, four women—two Ethiopians, a Kenyan and Hassan—took each other’s measure but no one was able to surge away for the win.

Hassan, who completed the unprecedented 1500/10,000 meter double at the 2019 Doha World Championships and who is the current world record holder in the women’s mile run, saved her kick until the final 200 meters of the 26.2-mile race.

Hassan’s victory had notable parallels to Hellen Obiri’s victory in the women’s race of the Boston Marathon, held on April 17. Like Hassan, the Kenyan Obiri has a pedigree from the track, including global medals at the 5000- and 10000-meter distances. Also battling rain and wet conditions, Obiri saved her kick for the homestretch of the race on Boylston Street, where she unleashed a ferocious kick to break apart a pack of runners all with substantially faster personal bests. Obiri finished at 2:21:38.

While both Obiri and Hassan ran impressive times on their respective courses, neither achieved times on par with the several historic performances in the last few years that have seen multiple women breaking 2:17. Still, their victories against competitive fields in less-than-ideal conditions have led both to be labeled early favorites for the marathon title at the 2024 Paris Summer Olympics.

In the men’s field in Boston, world-record holder Eliud Kipchoge led early at course record pace only to slow substantially over the famous Newton Hills in the mid-section of the race. Approximately 30 kilometers into the race (just past 18 miles), he missed a drinks station and began to exhibit a noticeable stride change as if the rainy conditions were causing his quadriceps to become overworked. He would fall off the pace and finish sixth. The race was won by Evans Chebet, the defending champion, in 2:05:54.

While Kipchoge at 38 years old insists he can still lower his current world record and seems likely to attempt to win his third Olympic gold medal in the marathon in Paris next year, his loss in Boston followed by a narrow miss on his world record in London suggests new generation marathoners are on the ascent.

Given Kiptum’s age and relative inexperience at the marathon, many observers believe he could take down Kipchoge’s much-heralded world record as early as this fall if he is offered good pacing on a course like Berlin or Valencia, which are statistically the fastest courses in the world.