The Dutchman has been chasing the leader’s jersey for most of the first week, and finally cracked his Colombian rival Chaves on the horrendously steep climb to the finish.
Dumoulin made his initial move further down, and spent most of the climb dangling just ahead of the chasing pack of favourites. It looked as though he had gone too early to win the stage, as a two-man chasing group of Chris Froome (Team Sky) and Joaquim Rodriguez (Katusha) caught him in the final kilometre.
But the sprint played out in a surprising fashion. Rodriguez made his move far too early, and then Froome also counter-attacking prematurely, allowing Dumoulin to claw his way back to the Briton’s wheel and pass him on the finishing straight for the win.
Despite missing out on the stage victory, it was still a hugely encouraging day for Froome. Questions had been asked about his form after he was dropped on stage seven’s finishing climb, but today it was he riding the GC contenders off his wheel, with the likes of Alejandro Valverde, Nairo Quintana (both Movistar) and Fabio Aru (Astana) all unable to keep up with his explosive pace.
Earlier on it had looked as though Movistar were the strongest, with both Valverde and Quintana putting digs in before Dumoulin made his move. These attacks were initially enough to drop Froome, but, as we’ve become used to seeing, the Sky rider paced his effort perfectly and surged past the pair later on the climb, putting 18 seconds into each of them.
Chaves fared worse still, finishing 59 seconds behind Dumoulin in fifteenth. He slips to third overall, with both Dumoulin and Rodriguez leapfrogging him in the general classification.
Despite the move up, Rodriguez will nonetheless be disappointed by his failure to win the stage, after his Katusha teammates spent most of the day setting the pace at the front of the peloton.
Geraint Thomas (Team Sky) was part of the day’s break that was caught at the bottom of the final climb. He joined Pavel Brutt (Tinkoff-Saxo) and Maxime Bouet (Etixx-Quick-Step) in an attack from the group with 10km to go, and did retain a lead of around a minute over the peloton with 7km left, but he never looked like staying away.
Omar Fraile was first over the day’s only other climb, the category two Paseo de Montana, and therefore retains his leadership of the mountains classification.
The riders now have just one mostly flat stage to negotiate tomorrow before the race’s first rest day.
10. Louis Meintjes (RSA), MTN-Qhubeka at 34s
Overall classification after stage nine
1. Tom Dumoulin (Ned), Giant-Alpecin
2. Joaquim Rodriguez (Esp), Katusha at 57s
3. Esteban Chaves (Col), Orica-GreenEdge at 59s
4. Nicolas Roche (Irl), Team Sky at 1-07
5. Alejandro Valverde (Esp), Movistar at 1-09
6. Fabio Aru (Ita), Astana at 1-13
7. Nairo Quintana (Col), Movistar at 1-17
8. Chris Froome (GBr), Team Sky at 1-18
9. Rafal Majka (Pol), Tinkoff-Saxo at 1-47
10. Domenico Pozzovivo (Ita), Ag2r-La Mondiale at 1-52