Two previous days of racing, and back-to-back victories no less, had begun to take its toll on Johannes Høsflot Klæbo within the first few laps of the men’s 15-kilometer freestyle pursuit on Sunday in Kuusamo, Finland. The 21-year-old Norwegian could feel it throughout his body; he was tired and 38 seconds of a starting cushion wasn’t going to be enough to hold off the hungry challengers behind him. Klæbo, who won Friday’s classic sprint and...