It is now Italian Aru that trails Spaniard Rodriguez by one second overall, with Rafal Majka (Tinkoff-Saxo) retaining his third place overall at 1-35. Dutchman Tom Dumoulin (Giant-Alpecin) put in a strong ride to keep his fourth spot at 1-51.
In front of the general classification fight, Frank Schleck (Trek Factory Racing) won the stage - his first Grand Tour win since a stage of the 2009 Tour de France. The 35-year-old from Luxembourg attacked from the day's escape group on another brutal mountain stage that incorporated seven categorised climbs tallying up over 5000 metres of ascent.
Rodolfo Torres (Colombia) placed second on the stage, with Moreno Moser (Cannondale-Garmin) in third.
Schleck had been part of an original 10-rider break also consisting of Torres, Moser, George Bennett (LottoNL-Jumbo), Omar Fraile (Caja Rural), Tsgabu Grmay (Lampre-Merida), Cyril Lemoine (Cofidis), Pierre Rolland (Europcar), Frank Schleck (Trek Factory Racing), Carlos Verona (Etixx-QuickStep) and Larry Warbasse (IAM Cycling).
The 10-rider group stretched out a lead of over 20 minutes mid-way through the stage, before the time gap started slipping back.
Fraile put himself into the group to snatch as many mountains points as possible to extend his lead in the KOM classification. He crested the first five climbs ahead, but a split in the lead group saw him distanced over the penultimate climb of Alto de la Cobertoria. At that point, Schleck and Torres had moved ahead of their former companions.
Schleck and Torres descended the Cobertoria together with over 10 minutes on the peloton. Fraile, Bennett and Verona were in a chase group behind them. Schleck attacked Torres with 3km to go, and Torres could not respond as Schleck ground his way out on the super-steep final section to take the stage win.
All the while, the peloton was also getting whittled down, with Astana leading the pace for Aru. However, Aru did not look comfortable and started to slip to the back of the group. Alejandro Valverde (Movistar) was one of the first of the big favourites to lose contact.
Dumoulin also struggled with the pace as the GC group passed under the final kilometre-to-go banner, and lost touch. Rodriguez chose this point to attack as Aru was again forced to chase, just as he did in the previous day's stage.
Rodriguez just about managed to put enough of a gap between himself and Aru to claim the overall lead going into the race's second rest day tomorrow. Dumoulin limited his losses, only losing 27 seconds to Rodriguez and will try and use his superior time trialling ability to overhaul his rivals when the race resumes on Wednesday with a 38.7km time trial in Burgos.
Vuelta a España 2015, stage 16: Luarca to Ermita de Alba, Quirós, 185km
1. Frank Schleck (Lux) Trek Factory Racing in 5-49-56
2. Rodolfo Torres (Col) Colombia at 1-10
3. Moreno Moser (Ita) Cannondale-Garmin at 1-48
4. George Bennett (NZl) LottoNL-Jumbo at 2-42
5. Pierre Rolland (Fra) Europcar at 2-49
6. Omar Fraile (Spa) Caja Rural-Seguros RGA at 3-05
7. Carlos Verona (Spa) Etixx-QuickStep at 4-26
8. Larry Warbasse (USA) IAM Cycling at 6-02
9. Joaquim Rodriguez (Spa) Katusha at 8-51
10. Fabio Aru (Ita) Astana at 8-53
11. Rafal Majka (Pol) Tinkoff-Saxo at 9-03
12. Nairo Quintana (Col) Movistar at same time
13. Mikel Nieve (Spa) Team Sky at 9-05
16. Tom Dumoulin (Ned) Giant-Alpecin at 9-18
Overall classification after stage 16
1. Joaquim Rodriguez (Spa) Katusha in 67-52-44
2. Fabio Aru (Ita) Astana at 1 sec
3. Rafal Majka (Pol) Tinkoff-Saxo at 1-35
4. Tom Dumoulin (Ned) Giant-Alpecin at 1-51
5. Mikel Nieve (Spa) Team Sky at 2-32
6. Esteban Chaves (Col) Orica-GreenEdge at 2-38
7. Daniel Moreno (Spa) Katusha at 2-49
8. Nairo Quintana (Col) Movistar at 3-11
9. Alejandro Valverde (Spa) Movistar at 3-58
10. Louis Mentjes (RSA) MTN-Qhubeka at 5-22
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