Fabio Aru (Astana) claimed the red jersey and all-but-sealed Vuelta a Espana victory after Tom Dumoulin’s challenge collapsed on the penultimate stage.

With just six seconds separating Giant-Alpecin’s race leader and Aru prior to the stage, the Italian attacked after a huge team effort on the penultimate climb, the Puerto de Morcuera.

As Ruben Plaza (Lampre-Merida) was bagging the stage victory from the break, Dumoulin tumbled down the overall standings after finally cracking, following three weeks of doggedly sticking with the GC men on the climbs.

Joaquim Rodriguez (Katusha) moved up to second overall, while Rafal Majka (Tinkoff-Saxo) will occupy the final podium spot barring any disasters on the flat, circuitous final stage.

The day boasted four category one climbs and a long descent to the finish, and the race for stage honours was always going to be secondary to the thrilling last rites of the GC battle.

As it was, a ten-man lead group went clear early on, including Plaza, and after splitting and re-forming several times there was eventually a group of 38 riders up the road which included Astana and Movistar riders to help their GC men later in the stage.

Giant-Alpecin seemed unconcerned with chasing it down, and as Plaza attacked on the day’s second climb it was Astana who set the pace in the peloton.

Dumoulin lost team-mates in the face of the Kazakh-backed team’s pressure, and it wasn’t long before Mikel Landa and Aru turned the screw further on the Morcuera, splitting the bunch with a stinging attack.

The Dutchman latched back on, but the attack had destroyed the GC group leaving just Aru, Landa, Dumoulin, Nairo Quintana (Movistar), Majka, Rodriguez, Johan Esteban Chaves (Orica-GreenEDGE) and Mikel Nieve (Team Sky).

Aru attacked again, with Quintana and Majka on his wheel, as they approached the penultimate summit – this time ridding themselves of Dumoulin’s attention.

The time trial ace did close the gap back to nine seconds, but as Aru picked up the remnants of the day’s break – including team-mate Luis Leon Sanchez – the gap went back out again and a disconsolate Dumoulin could sense his chances disappearing.

Back up the road, Plaza held his lead right up until the finish to bag stage victory but more drama was unfolding in the GC group as Rodriguez saw his hopes of a podium finish put under pressure.

With Majka and Quintana attacking, Rodriguez had to rally in the group containing Aru, Landa, Chaves and Sanchez but did so sufficiently to save second – setting up the fifth Grand Tour podium finish of his illustrious career.

The red jersey, however, will be worn into Madrid by Aru – in the process rescuing a race which started with team-mate Vincenzo Nibali’s disqualification and announcing his own serious Grand Tour potential.

Vuelta a Espana 2015: stage 20 – result

1) Ruben Plaza (ESP) – Lampre-Merida – 4.37.05hrs
2) Jose Goncalves (POR) – Caja Rural-Seguros +1.07
3) Alessandro de Marchi (ITA) – BMC Racing +1.08
4) Romain Sicard (FRA) – Team Europcar +1.29
5) Amael Moinard (FRA) – BMC Racing +1.30
6) Carlos Verona (ESP) – Etixx-QuickStep – ST
7) Sergio Henao (COL) – Team Sky
8) Kenny Elissonde (FRA) – FDJ +1.35
9) Matteo Montaguti (ITA) – Ag2r-La Mondiale +1.43
10) Moreno Moser (ITA) – Cannondale-Garmin +2.40

General classification

1) Fabio Aru (ITA) – Astana – 83.01.40hrs
2) Joaquim Rodriguez (ESP) – Katusha +1.17
3) Rafal Majka (POL) – Tinkoff-Saxo +1.29
4) Nairo Quintana (COL) – Movistar +2.02
5) Johan Esteban Chaves (COL) – Orica-GreenEDGE +3.30
6) Tom Dumoulin (NED) – Giant-Alpecin +3.46
7) Alejandro Valverde (ESP) – Movistar +7.10
8) Mikel Nieve (ESP) – Team Sky +7.26
9) Daniel Moreno (ESP) – Katusha +7.32
10) Louis Meintjes (RSA) – MTN-Qhubeka +10.46