Thomas De Gendt (Vacansoleil-DCM) has won Stage 20 of the Giro. The Belgian stormed up the Stelvio Pass to win the mountainous, 219-km ride from Caldes/Val di Sole to Passo dello Stelvio in 6:54:41. Damiano Cunego (Lampre-ISD) took the runner-up spot at 0:56, and Mikel Nieve (Euskaltel-Euskadi) finished third at 2:50. Joaquim Rodriguez (Katusha) remains the maglia rosa.

The break of the day made its getaway on the day's first climb, the Category 2 Passo del Tonale (32 km). Christian Vande Velde (Garmin-Barracuda), Roman Kreuziger (Astana), Damiano Caruso (Liquigas-Cannondale), Jose Serpa (Androni Giocattoli-Venezuela), Branislau Samoilau (Movistar), Oliver Zaugg (RadioShack-Nissan), Marco Carrara (Vacansoleil-DCM), Mathias Frank (BMC), Matteo Bono (Lampre-ISD), Alexander Kristoff (Katusha), Tom Slagter (Rabobank), and Matteo Rabottini (Farnese Vini-Selle Italia) sallied off of the front. The escapees led the field by 6 minutes on the day's second climb, the Category 3 Aprica, but the lead was down to 3 and a half minutes when the break reached the Category 1 Mortirolo.

The Mortirolo broke up the break. Four km from the summit, Zaugg and Carrara led the stage. Behind, Lampre-ISD paced the field on behalf of Michele Scarponi. The Italian squad's pacemaking tore the bunch apart.

Carrara fell back, and Caruso moved up. Vande Velde and Serpa teamed up with Serpa. Rabottini was dropped.

Vande Velde and Serpa dropped Carrara and bridged up to Caruso and Zaugg. Andrey Amador (Movistar) joined the leaders.

At the summit, Zaugg attacked. Vande Velde dropped back to the maglia rosa group, and De Gendt attacked. A number of riders attempted to follow. With 40 km left, the maglia rosa group trailed Zaugg by 6 minutes.

A six-man chase group formed to pursue Zaugg. With 30 km left, the chasers caught the Swiss rider. The leading septet led the maglia rosa group by 4 minutes when it reached the Stelvio.

Zaugg was dropped. With 16 km remaining, De Gendt attacked. Nieve joined him, and 3 km later, Cunego followed suit.

De Gendt attacked again and dropped the pair. At one point, he led the maglia rosa group by 4 minutes and was a threat to Ryder Hesjedal's (Garmin-Barracuda) second on GC. With 10 km left, the Belgian led the maglia rosa group by 5:05.

Hesjedal unsuccessfully attempted to persuade the remainder of the maglia rosa group to chase De Gendt. John Gadret (Ag2r-La Mondiale) attacked, and the Sky duo of Rigoberto Uran and Sergio Henao attempted to pull the maglia rosa group to the Frenchman. Little progress was made, however.

With 2 km left, Hesjedal took matters into his own hands. The Canadian attacked, and Domenico Pozzovivo (Colnago-CSF Inox), Uran, and Ivan Basso (Liquigas-Cannondale) were dropped. Scarponi countered and dropped the Canadian and Rodriguez. Rodriguez attacked and overtook Scarponi in the last 200 m. Rodriguez kept the maglia rosa, Hesjedal his runner-up spot, and Scarponi his third place, while De Gendt's exploit propelled him from 8th to 4th overall.

In the overall, Rodriguez leads Hesjedal by 0:31 and Scarponi by 1:51. Stage 21, a flat, 28-km time trial in Milan, will decide the winner of the 2012 Giro. Rodriguez, a mediocre time trialist, stands to lose his maglia rosa to Hesjedal and has said so. Other places will be up for grabs, as 1:52 separate Scarponi in 3rd from Cunego in 6th. In addition, 1:33 separate Pozzovivo in 8th from Henao in 11th.

How will matters shake out? Check in at www.roadcycling.com and find out!