A 17-man breakaway representing 17 different teams escaped the peloton 20km into the stage. The escape group included Emanuele Sella (Androni Giocattoli-Venezuela), Stefano Pirazzi (Colnago-CSF Inox), Serge Pauwels (QuickStep), Sandy Casar (FDJ-BigMat), Thomas Rohregger (RadioShack-Nissan), Andrea Guardini (Farnese Vini-Selle Italia),  and Juan Antonio Flecha – the first time a Sky rider has been in a breakaway in this entire race. (Liquigas are now the only team not to have put a man in a break.)

By the initial first category climb of the day, the Passo Manghen, their advantage was around ten minutes over the Liquigas-led peloton. 17 soon became 16 as Guardini was quickly jettisoned on the ascent. (The winner of yesterday’s stage would eventually finish alone, nearly 47 minutes down and 5½ minutes behind the next rider.) Pirazzi led Rohregger over the summit followed by Casar, with the peloton six minutes in arrears.

Rohregger initially led on the first ascent of the Pampeago began, but was soon dropped by the other two. Pirazzi again crossed the summit first, uncontested by Casar. With Liquigas setting a relentless tempo at the front, the peloton quickly began to thin out, with eighth-placed Paolo Tiralongo (Astana) the most notable casualty, as they followed over the top with a reduced deficit of 3½ minutes.

Omega Pharma-Quick Step’s Dario Cataldo was subsequently allowed to attack off the front of the bunch, followed by Astana’s Kevin Seeldraeyers. The latter’s move was to set up an attack by teammate Kreuziger, who bridged across on the penultimate climb of the Passo Lavaze and soon left him behind. Pirazzi again led Casar over the summit, with Rohregger and Sella 25 seconds behind, Kreuziger, Cataldo and Pauwels at 1:53, and the peloton a further minute back as they started the final descent.

Scarponi initiates the selection as Kreuziger solos to victory

The time gaps between the lead groups held constant on the descent, leaving the peloton just over three minutes behind Casar and Pirazzi as they started the final climb. The pair were briefly joined by Rohregger and Sella, only to fall away again. Behind them Kreuziger was drawing inexorably closer. He made short work of Rohregger and Sella, and soon bridged across to Casar, who had by now been dropped by Pirazzi. The Frenchman was able to tuck into his slipstream for a while before he too fell away just as the climb reached its steepest section in the final 3km. Pirazzi too was soon despatched with, leaving the Czech to exercise his full range of pained facial contortions as he laboured on alone towards the finish.

Behind him an ever decreasing chase group featuring most of the top ten rode quickly but watchfully up the early part of the climb as the favourites kept a close eye on each other for any signs of weakness. With the unrelenting gradient offering little opportunity for respite, even top men Ivan Basso (Liquigas), Michele Scarponi (Lampre-ISD), Ryder Hesjedal (Garmin-Barracuda) and maglia rosa Joaquim Rodriguez (Katusha) were visibly on the rivet, and unsurprisingly none were willing to push themselves into the red with a premature attack. Even without sudden accelerations, however, this lead chase group was soon reduced to just six: the aforementioned quartet plys Sky’s Rigoberto Uran and stage eight winner Domenico Pozzovivo (Colnago).

Ultimately it was defending champion Scarponi who broke the stalemate, launching a series of three attacks from just inside 4km. In each case it was noticeable that Hesjedal was the first to respond, with Pozzovivo the first to start yo-yoing off the back of the group. Scarponi’s third attack stretched the elastic to its limit, with only Hesjedal and Rodriguez able to follow immediately, while Basso, Uran and Pozzovivo had to strain every sinew to claw their way back inch by inch.

With his rivals visibly weakened by the champion’s attacks, Hesjedal picked his moment to almost imperceptibly slip up a gear and accelerate away. Only Scarponi followed, but he too soon found himself sliding backwards off the Canadian’s wheel. Grimacing with the effort, Hesjedal set off in pursuit of Kreuziger. As he passed the 2km board the gap was 45 seconds, but as he approached the last few hundred metres the slowing Astana rider hoved into view. If the stage had been another 500 metres longer he might well have caught him, but Kreuziger held on to win, throwing his arms briefly aloft as he crossed the line, exhausted.

After the stage, Kreuziger was pleased to have won a stage, but admitted it was no more than a consolation prize:

For sure I came to the Giro to get a good result on GC. I lost morale at Cortina. Today’s stage win shows that my spirit is intact but it cannot bring me the same satisfaction as finishing in the top three.

Hesjedal emptied his tank in pursuit of precious seconds, finishing 19 seconds adrift of the winner but 13 ahead of the pink jersey, who caught and passed an ashen Scarponi in the last 50 metres. Pozzovivo finished alone in fifth, with Basso sixth 55 seconds down on Kreuziger – andcritically  36 on Hesjedal – a few metres ahead of the white jersey of Uran.

Rodriguez’s fourth place kept him in pink, albeit by the reduced margin of 17 seconds, and also moved him to within 13 points of Mark Cavendish – who finished with the gruppetto safely inside the time limit – in the battle for the points jersey. A top four finish on tomorrow’s stage will deny the world champion a first maglia rosso and prevent him becoming only the fifth rider ever to win the points jerseys at the Giro, Tour and Vuelta.

However, with Hesjedal consolidating his position in second ahead of tomorrow’s final mountain stage, it is the Canadian who is now firmly in the driver’s seat. If he can defend his position on the Stelvio tomorrow with no or minimal losses he will start Sunday’s concluding time trial as the runaway favourite for overall victory. Despite still being in possession of the maglia rosa, Rodriguez admitted as much after the stage:

Today was a day when we all needed to take time on Hesjedal and instead he took time on us. I am happy to have kept the pink jersey, but if Ryder continues like this, this Giro will be his. I have improved a lot in the time trial, but Ryder will have had to become a lot worse if I can expect to keep pink on Sunday with these differences. My only hope now is that he has a bad day tomorrow.

Despite leapfrogging over Basso into third after a swashbuckling ride, Scarponi admitted that his only hope of successfully defending the title he inherited from Alberto Contador is to make Hesjedal crack on the Stelvio tomorrow:

I was confident I could attack and I wanted to, but sometimes the tactics that we make inside the team bus do not translate onto the race. This final mountain stage tomorrow will mean suffering for all of us. If Ryder doesn’t have a bad moment, this Giro looks like it’s his. The only answer is to attack.

The stage is set for one final showdown on the highest finish ever at a Grand Tour. The Passo dello Stelvio will test Hesjedal’s defences to their limit as Rodriguez, Basso and Scarponi are left with no option but to throw caution to the winds if they are to take time out of him ahead of Sunday’s individual time trial, where the Canadian should be the fastest of the four main contenders. It should be epic.

VeloVoices rider of the stage: A toss-up between Stefano Pirazzi, who rode bravely at the front all day but ran out of steam towards the end, and defending champion Michele Scarponi, who showed tremendous battling qualities in animating the final 4km with his repeated attacks. I’ll go with Pirazzi.

Stage 19 result:

1. Roman Kreuziger (Astana) 6:18:03

2. Ryder Hesjedal (Garmin-Barracuda) +0:19

3. Joaquim Rodriguez (Katusha) +0:32

4. Michele Scarponi (Lampre-ISD) +0:35

5. Domenico Pozzovivo (Colnago-CSF Inox) +0:43

General classification:

1. Joaquim Rodriguez (Katusha) 84:06:13

2. Ryder Hesjedal (Garmin-Barracuda) +0:17

3. Michele Scarponi (Lampre-ISD) +1:39

4. Ivan Basso (Liquigas-Cannondale) +1:45

5. Rigoberto Uran (Sky) +3:21

6. Domenico Pozzovivo (Colnago-CSF Inox) +3:30

7. John Gadret (AG2R La Mondiale) +5:36

8. Thomas De Gendt (Vacansoleil-DCM) +5:40

9. Sergio Henao (Sky) +5:37

10. Damiano Cunego (Lampre-ISD) +6:09

Points leader: Mark Cavendish (Sky).

King of the Mountains leader: Matteo Rabottini (Colnago-CSF).

Tomorrow: Stage 20 – Caldes/Val di Sole to Passo dello Stelvio, 219km. Even a sizeable time gap could quickly fritter away on the final (and, at 219km, the longest) day in the mountains, with two iconic climbs – the Mortirolo and the giant 2,757-metre Stelvio (think of the Galibier, but 112 metres higher) – set to exact final punishment on the maglia rosa aspirants. There is barely a flat section worth the name from the outset as the road heads uphill almost straight away and switches between incline and decline almost constantly thereafter. The second category Passo del Tonale (15.1km, 6.1%) is a mere hors d’oeuvre before the mighty Mortirolo. The 11.4km climb averages 10.5% overall, but most of its first half is above 12%, while the final 2km averages an eye-watering 13.7% with some sections touching 22%. For whoever is still standing at the foot of the Stelvio, the good news is that the gradient rarely strays far from its average 6.9% – the bad news is it takes 22.4km to reach the summit. Hesjedal only needs to defend on this final climb – Basso, Scarponi and Rodriguez must attack.