Rupp, who is a former track star and three-time Olympian, finished the Boston Marathon in second place past year and became the first American since 1964 to win a medal in the 10,000 meters at the 2012 London Olympics.
Rupp surged ahead for good with three miles remaining to win in 2hrs 9mins 20secs with Kenyan runner-up Abel Kirui, the defending champion, 28 seconds back and Bernard Kipyego, also of Kenya, third in 2:10:23. Rupp, who finished second in the Boston Marathon in April, is the first American male to win the race since Khalid Khannouchi in 2002. Shortly after 21.1K, Dennis Kimetto, the men's world record holder, stepped off the course limping with an apparent injury, continuing his recent struggles that have plagued him for the past two years. Together, she and McFadden have won every Chicago Marathon since 2007. Dibaba was out in front on her own, having gapped Kosgei, while Kirui, Rupp and Ethiopian Sisay Lemma were in contention duking out who would finish where on the men's podium.
Rupp is a three-time U.S. Olympian.
"I hadn't really planned out when I was going to go but I definitely wanted to wait until 20 to 22 miles", Rupp said after the race.
Dibaba led at the halfway mark at 1:08:48, well off Radcliffe's record pace, but made another charge that left only Kosgei on her heels.
But ultimately she came up slightly short of the course record. Dibaba is a three-time Olympic gold medalist and has won five World Championship track gold medals. Previous year in Rio, Dibaba was third in the 10,000. He won the Olympic Trials Marathon in February 2016 in his debut, then claimed Olympic bronze in Rio de Janeiro and finished second in the 2017 Boston Marathon in April.