Korir, whose victory in the 2024 Chicago Marathon in a time of 2:02:44 made him the sixth fastest marathoner in history, clocked 2hr 04min 45sec for the win.
The 28-year-old’s feat emulated that of his brother Wesley Korir, the now-Kenyan politician, having won in Boston in 2012 on his first attempt in five appearances.
Tanzania’s 2017 world bronze medallist Alphonce Felix Simbu was second, just holding off Kenya’s Cybrian Kotut in a photo-finish in 2:05.04.
The first American home was Conner Mantz in fourth, missing out on a podium place by just four seconds, a time that was also just eight seconds off Ryan Hall’s fastest US marathon time ever.
Lokedi timed 2:17:22 in the women’s race, outpacing Obiri by 19 seconds, with Yalemserf Yehualaw rounding out the podium.
She smashed the previous course record of 2:19:59 set by Ethiopia’s Buzunesh Deba in 2014.
The men’s field included 21 sub-2:09 runners, but none could get close to Kenyan Geoffrey Mutai’s course record of 2:03.02 set back in 2011.
US Olympian Mantz took the lead group of 21 runners through the 5km mark in 14:20 in a marathon which first saw men compete back in 1897.
By the 10km mark, hit in 28:52, defending champion Sisay Lemma had taken up the front running, and the pack fell to 16 5km later.
Rory Linkletter led Lemma through halfway in 1:01.52, but the pace proved too much for the Ethiopian, who promptly dropped out just after 1:19 on the road.
Coming to the business end of the race, Korir, Mukhtar Edris, Daniel Mateiko and two-time winner Evans Chebet were all in the running in a lead field 13 deep, Mantz doing the majority of the pace setting.
Korir made his move around the 34km mark, surging to take a lead he would never cede.
He quickly built it up to nearly a minute as the others scrambled not only to reel him in but also fight for podium spots.
Korir held his nerve as Kotut and Simbu surged through themselves to stage their own mini-battle for second place, Mantz doing well for fourth as Edris faded into fifth spot.
Obiri had been looking to become the first woman since 1999 to win three consecutive Boston Marathon titles, something only four women have ever done.
Only Deba had broken 2:20 pace in Boston, but a group of 14 remained on track for that mark at the halfway point.
The pack split, but Obiri had not counted on Lokedi’s electric finish, the 31-year-old pulling clear at the death for a new Boston record, with 32,000 participants on the heels of the elite runners. (AFP)
