Twenty-two year old Formolo (Cannondale-Garmin) attacked his breakaway companions with 13km to go and managed to hold off the strongest riders in the race to claim stage honours, in what's his Grand Tour debut.
"The final 500m were absolutely incredible. The noise of the crowd made the hairs stand up on the back of my neck. I only knew I'd won the stage 100m from the finish line. I wasn't thinking of the Maglia Rosa. I'm riding my first Giro d'italia, so I'm taking it day by day and there is no pressure on me. We're riding for Hesjedal in the GC, so I don't know if I'll get another chance." - Davide Formolo.
For the second day in a row Clarke found himself in a break late in the race, and having been dropped earlier, Clarke fought hard to regain contact with the chase group that featured Alberto Contador (Tinkoff-Saxo), Richie Porte (Sky) and Fabio Aru (Astana). Clarke threw his arms in the air as he sprinted to second place in La Spezia. The group finished 22 seconds down, ensuring that the Australian would take the race lead from team-mate Michael Matthews who was unable to keep pace with the leaders on the hilly 150km stage.
"You saw the emotion crossing the line," said Clarke who put his own chances on the line in Stage 3 to deliver Matthews a stage victory. "I was just stoked to keep the jersey in the team. I knew the Cannondale rider was up the road but I couldn't hold the emotion in to have been able to take the jersey and keep it in Orica for another day.
"The plan was always to ride for a sprint yesterday but it's never enjoyable being ridden back by your own team. I wasn't disappointed at all, I went into yesterday's stage fully aware that was the plan so I knew what it was going to come down to. I was just glad to be able to bounce back again today and prove that I am going well and that I deserve to have the jersey for at least a day." - Simon Clarke.
The intense stage proved to be the first time the general classification contenders showed their hands, with Etixx-Quick-Step's Rigobero Uran the biggest loser. The Colombian could not follow when Aru launched an attack on the category three Biassa climb, less than 15km from the finish. Contador, Porte and Van der Broeck could all follow, merging with the remants of the break, and leaving only Formolo clear in front.
Clarke holds a 10 second lead over team-mate Esteban Chaves while Tinkoff-Saxo's Roman Kreuziger has moved up to third. There was no changes to the time gaps that separated the contenders from the leader's jersey with Contador still 17 seconds back, Aru 23 seconds and Porte 37 seconds in arrears. Uran lost 42 seconds on the stage to now sit 1min 11sec off the pace.
The fourth stage was characterised by relentless climbing and narrow winding roads. An early selection eventually gave way to a large group at the front of the race that consisted of at least 28 riders.
Orica-GreenEDGE was well-represented at the front of the race with Clarke, Esteban Chaves and Pieter Weening, taking the pressure off race leader Michael Matthews back in the peloton. Also featured in the selection was Contador’s Tinkoff-Saxo team-mate Roman Kreuziger, Dario Cataldo (Astana), Darwin Atapuma (BMC), Tom Danielson (Cannondale-Garmin) and Franco Pellizotti (Androni Giocattoli).
The group held a nine minute advantage with 80km and two categorised climbs to go, but in such a large group, the co-operation of the riders suffered. Attacks were frequent as teams tried to shed riders; finally one stuck.
A group of seven riders rode clear of the breakaway on the early slopes of the category three climb to Passo del Termine. At this point Astana had put five riders on the front of the peloton to drive the chase with their efforts significantly diminishing the size of the peloton, with many riders, including Matthews, dropped.
The groups at the front of the race - the seven rider group and their former breakaway companions - came together over the top of the Passo del Termine to form a group of 15 riders with Orica-GreenEDGE’s pair of Chaves and Clarke still present.
With the base of the Biassa approaching, Formolo made his move. Giovanni Visconti (Movistar) and Amael Moinard (BMC) set off in pursuit but they could not close the gap to the Italian he established over a one minute lead to the peloton.
Further back on the road Aru attacked, with Contador and Porte hugging his wheel. The group was quick to reach the riders who were chasing Formolo.
Clarke fought hard to remain with the leaders over the top of the climb. Knowing that the Maglia Rosa was at stake he dug in on the descent, eventually making contact with the group with six kilometres to go to secure himself his first Grand Tour's leader's jersey.
The 150km fifth stage from La Spezia to Abetone will again see the general classification riders in action with the first summit finish of the Tour.
Stage 4: 150km, Chiavari - La Spezia
1 Davide Formolo (ITA) Cannondale-Garmin 3hr 47min 59sec
2 Simon Clarke (AUS) Orica-GreenEDGE 0:00:22
3 Yonathan Monsalve (VEN) Southeast
4 Giovanni Visconti (ITA) Movistar
5 Esteban Chaves (COL) Orica-GreenEDGE
6 Fabio Aru (ITA) Astana
7 Amael Moinard (FRA) BMC
8 Dario Cataldo (ITA) Astana
9 Alberto Contador (ESO) Tinkoff-Saxo
10 Richie Porte (AUS) Sky
1 Simon Clarke (AUS) Orica-GreenEDGE 11hr 54min 48sec
2 Esteban Chaves (COL) Orica-GreenEDGE 0:00:10
3 Roman Kreuziger (CZE) Tinkoff-Saxo 0:00:17
4 Alberto Contador (ESP) Tinkoff-Saxo
5 Fabio Aru (ITA) Astana 0:00:23
6 Dario Cataldo (ITA) Astana
7 Giovanni Visconti (ITA) Movistar 0:00:29
8 Amael Moinard (FRA) BMC 0:00:31
9 Davide Formolo (ITA) Cannondale-Garmin
10 Richie Porte (AUS) Sky 0:00:37