Britain's Simon Yates limited his losses to Giro d'Italia leader Primoz Roglic after crashes split the race in a dramatic finale to stage four.
Roglic made it into a small front group following a series of crashes with 6km to go before Ecuador's Richard Carapaz attacked late on to win in Frascati.
Yates was brought down in the last crash but chased back to lose only 16 seconds to Roglic and stay in second.
Tom Dumoulin, the 2017 champion, fell heavily and finished four minutes down.
"Everyone was fighting for position on a roundabout with about 6km to go and a rider slid out in front of me," Mitchelton-Scott rider Yates told Eurosport.
"I'm not blaming anybody, these things happen, but I got up quickly and had the guys around me to limit the losses.
"My knee and hip are patched up, it's just left hand side, but I'm OK - it's always worse in the morning so we'll see but the Giro is long."
Yates is now 35 seconds down on Slovenian Roglic in the overall standings, with Italian Vincenzo Nibali four seconds back in third.
Team Ineos' Tao Geoghegan Hart, who lost 88 seconds on stage three, was caught behind a crash for the second day in a row but made it into the Yates group that finished 18 seconds down on stage winner Carapaz.
Dumoulin, who started the day in fifth overall, was taken to hospital but Team Sunweb later announced he had not sustained any fractures.
The Dutchman said his knee is "very swollen" and he will decide on Wednesday whether to start stage five, adding "the GC is for sure gone".
After a largely straightforward day, the racing became more frantic in a technical finale, with Britain's James Knox crashing at 12km to go in the 235km stage from Orbetello.
Team Ineos rider Salvatore Puccio then slipped as the road narrowed at 6.4km to go, causing a large crash that brought down Dumoulin and held up most of the peloton.
Yates was caught up in a subsequent crash, which left only seven riders out front to contest the slightly uphill finish.
Carapaz, who finished fourth in last year's Giro, caught out his rivals by kicking away at 500m to go, with sprinter Caleb Ewan setting off in pursuit but unable to overhaul the Movistar rider, while Diego Ulissi held on for third.
Roglic did not compete for the bonus seconds, rolling in two seconds down on Carapaz in sixth.
Stage five is a flat 140km course from Frascati to Terracina.
Stage four results
1. Richard Carapaz (Ecu/Movistar) 5hrs 58mins 17secs
2. Caleb Ewan (Aus/Lotto-Soudal) Same time
3. Diego Ulissi (Ita/UAE Team Emirates)
4. Pascal Ackermann (Ger/Bora-Hansgrohe) +2secs
5. Florian Senechal (Fra/Deceuninck-Quick-Step) Same time
6. Primoz Roglic (Slo/Team Jumbo-Visma)
7. Valerio Conti (Ita/UAE Team Emirates) +14secs
8. Miguel Angel Lopez (Col/Astana) +18secs
9. Arnaud Demare (Fra/Groupama-FDJ) Same time
10. Simon Yates (GB/Mitchelton-Scott)
General classification after stage four
1. Primoz Roglic (Slo/Team Jumbo-Visma) 16hrs 19mins 20secs
2. Simon Yates (GB/Mitchelton-Scott) +35secs
3. Vincenzo Nibali (Ita/Bahrain - Merida) +39secs
4. Miguel Angel Lopez (Col/Astana Pro Team) +44secs
5. Diego Ulissi (Ita/UAE Team Emirates) Same time
6. Rafal Majka (Pol/Bora-Hansgrohe) +49secs
7. Bauke Mollema (Ned/Trek-Segafredo) +55secs
8. Damiano Caruso (Ita/Bahrain-Merida) +56secs
9. Bob Jungels (Lux/Deceuninck-Quick-Step) +1min 02secs
10. Davide Formolo (Ita/Bora-Hansgrohe) +1min 06secs
13. Hugh Carthy (GB/EF Education-First) +1min 16secs
30. Tao Geoghegan Hart (GB/Team Ineos) +2mins 19secs
56. Tom Dumoulin (Ned/Team Sunweb) +4mins 30secs
131. James Knox (GB/Deceuninck-Quick-Step) +15mins 48secs
156. Scott Davies (GB/Dimension Data) +26mins 55secs