Everyone remembers their toughest day on a bike, even the professionals.

For Katusha sprinter Alexander Kristoff, that day came on stage 15 of the 2011 Giro d’Italia. That stage featured no less than five categorised climbs, including a ride over the Cima Coppi for that year, the Passo Giau as well as a summit finish.

>>> My toughest day: Sean Kelly

The latter part of Grand Tours is always a tough one for the fast men as the races usually hits the mountains, but a staggering nine hours in the saddle is telling for even the most hardened rider.

Here Norweigian Kristoff tells us why that stage, won by Spaniard Mikel Nieve, sits long in his memory, as he battled sickness as well as the distance and the terrain. And not only did he have to finish the stage, he had to ride back down the mountain to the team bus as well!