Rarely has there been more to play for in a final week time trial at a Grand Tour, but on stage 17 of the Vuelta a España the whole race could be turned on its head and we may see a quite unexpected rider topping the leaderboard.
Tom Dumoulin heads into the 38.7km as the strong favourite to win the stage, but sitting just 1-51 behind leader Joaquim Rodriguez, and with no strong time trialists ahead of him, he could take over the race lead tonight.
Dr Hutch talks us through the tactics behind a long time trial
With 167 riders left in the race, Lanterne Rouge Boy Van Poppel sets off first at 12:34 (BST), with a one-minute time gap between each rider outside the top 30.
When we get down to Nicolas Roche, who sits in 30th, the time gaps expand to two minutes, with Rodriguez the last man out the gate at 15:49.
Selected start times
Steve Cummings (MTN-Qhubeka) 13:42
Andrew Talansky (Cannondale-Garmin) 13:46
Vasil Kiriyenka (Team Sky) 13:54
Geraint Thomas (Team Sky) 14:20
Alejandro Valverde (Movistar) 15:31
Louis Meintjes (MTN-Qhubeka) 15:33
Nairo Quintana (Movistar) 15:35
Dani Moreno (Katusha) 15:37
Esteban Chaves (Orica-GreenEdge) 15:39
Mikel Nieve (Team Sky) 15:41
Tom Dumoulin (Giant-Alpecin) 15:43
Rafal Majka (Tinkoff-Saxo) 15:45
Fabio Aru (Astana) 15:47
Joaquim Rodriguez (Katusha) 15:49