Winning any title in sports twice in a row is a challenge. The element of surprise is gone. Expectations rise. The rest of the field is out to topple the champion. It’s one reason so few men have won back-to-back titles at the New York City Marathon.

Geoffrey Kamworor isn’t taking the challenge lightly. The 25-year-old Kenyan, who won last year’s race by three seconds, is back in New York aiming to become only the second male runner in the past two decades, and the seventh in the 48-year history of the race, to win consecutive titles. He knows the field, stacked with other Olympians and major marathon winners, will be gunning for him.

Kamworor has a secret weapon though: his training partner. Six days a week for most of the year, he runs stride for stride in Kenya with Eliud Kipchoge, the world-record holder in the marathon and the greatest marathoner ever.

In many ways, the runners have a mentor-protégé relationship. Kipchoge is older by eight years and has already made the progression from the track to road racing and marathons. Over time, he has focused on fewer races with bigger impact, something Kamworor is starting to do.