Richard Carapaz won stage four of the Giro d'Italia from a small group after crashes tore the peloton apart in the final.
The Ecuadorian rider made it into an eight-rider split that rode away after a big crash that took out a number of overall favourites 5km from the line.
Primož Roglič (Jumbo-Visma) avoided the collision and finished in the front group to hold on to the maglia rosa, while all his rivals lost time because of the crash.
Tom Dumoulin's (Sunweb) chances of winning the Giro this year are almost certainly over after the Dutchman was caught in the crash, suffering a knee injury and losing more than four minutes.
Simon Yates (Mitchelton-Scott) and Vincenzo Nibali (Bahrain-Merida) also lost time to Roglič but still remain in the fight for the overall.
How it happened
After the post-race drama on stage four, the peloton will have been on the hunt for a clean win on the undulating roads of stage five.
The parcours for day five, running over 235km from Orbetello to Frascati, just outside Rome, offered a number of potential victors with pundits calling a day for the climbers while others believed the sprinters could go to the line.
After cresting the only classified climb along the route - the category four rise to Manciano in the opening 35km - the peloton would then roll through the unclassified hills of Italy's west coast with an eye on the final 25km, which marked the start of a long and gradual rise to the line.
At the 210km, mark, the roads began to slope gradually upwards, with a few brief downhill moments of respite, before the 2.2km-long climb to the line averaging 4.5 per cent gradient.
The day's breakaway formed early as three Italian riders attacked from kilometre zero and the bunch were content to let them escape.
Mirco Maestri (Bardiani-CSF), Damiano Cima (Nippo-Vini Fantini-Faizanè) and Marco Frapporti (Androni Giocattoli-Sidermec) all went clear and were allowed a significant gap early on, building up almost six minutes in the first kilometre.
The peloton were content to leave the home trio out front as the gap built to more than 12 minutes at just the 35km mark before teams began to take the race on, most notably Lotto-Soudal who worked to close down the advantage for their versatile sprinter Caleb Ewan.
Lotto's efforts pulled the breakaway back within eight minutes, but the three out front were able to extend their lead out to nine minutes once again.
As the race entered the final 60km, the peloton turned their focus to the line and upped the pace to bring Maestri, Cima and Frapporti back to 5-18, with Deceuninck - Quick-Step, Bora-Hansgrohe and Lotto-Soudal doing most work, while Jumbo-Visma were ever-present near front with their race leader Roglič.
The breakaway refused to capitulate and the gap extended back out to just over six minutes inside 50km.
A relaxed peloton slowly ground the escapees down, when Cima was finally dropped from the front group as Maestri and Frapporti pushed on inside 20km.
The pair held one-minute at the 15km mark, but the gap began to tumble rapidly as the bunch began to drive behind.
A crash hit the peloton 12km from the line, with James Knox (Deceuninck - Quick-Step) hitting the deck for a second day in a row.
The Brit stopped at the side of the road but the extent of his injuries were unclear.
Maestri and Frapporti were then picked up by the bunch with just over 10km to race, as frantic racing continued.
A big crash 5km from the line tore the peloton apart as a handful of riders made it through unscathed and made a dash for the line.
Roglič, Carapaz, and Ewan were all part of an eight rider group that hit the final climb together as the rest of the favourites for the stage and overall picked themselves up from the floor.
UAE Team Emirates set a high pace in the front group to set up Diego Ulissi, but it was Carapaz who broke free with a huge acceleration 500m from the line.
Ewan then opened up his sprint to chase down the attack but faded at the line as Carapaz raised both arms in celebration.
Dumoulin came off worst amongst the GC favourites, suffering a big gash in his knee and finishing four minutes down.
Simon Yates and Nibali both lost 16 seconds to Roglič, leaving them 35 and 39 seconds down respectively.
The race continues with another sprint day on stage five over 140km from Frascati to Terracina, opening with some sharp uncategorised climbs before a fourth category rise in the middle of the day. A long and fast run to the line then follows in the final 40km.
Giro d'Italia 2019, stage four: Orbetello to Frascati (235km)
1. Richard Carapaz (Ecu) Movistar, in 5-58-17
2. Caleb Ewan (Aus) Lotto-Soudal
3. Diego Ulissi (Ita) UAE Team Emirates, all at same time
4. Pascal Ackermann (Ger) Bora-Hansgrohe, at 2 seconds
5. Florian Sénéchal (Fra) Deceuninck - Quick-Step
6. Primož Roglič (Slo) Jumbo-Visma, all at same time
7. Valerio Conti (Ita) UAE Team Emirates, at 14s
8. Miguel Ángel López (Col) Astana, at 18s
9. Arnaud Démare (Fra) Groupama-FDJ
10. Simon Yates (GBr) Mitchelton-Scott, all at same time
General classification after stage four
1. Primož Roglič (Slo) Jumbo-Visma, in 16-19-20
2. Simon Yates (GBr) Mitchelton-Scott, at 35s
3. Vincenzo Nibali (Ita) Bahrain-Merida, at 39s
4. Miguel Ángel López (Col) Astana, at 44s
5. Diego Ulissi (Ita) UAE Team Emirates, at same time
6. Rafał Majka (Pol) Bora-Hansgrohe, at 49s
7. Bauke Mollema (Ned) Trek-Segafredo, at 55s
8. Damiano Caruso (Ita) Bahrain-Merida, at 56s
9. Bob Jungels (Lux) Deceuninck - Quick-Step, at 1-01
10. Davide Formolo (Ita) Bora-Hansgrohe, at 1-06
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