Enrico Battaglin claimed his first Giro d'Italia stage win on Tuesday with fellow Italian Luca Paolini retaining the leader's pink jersey and race favourite Bradley Wiggins losing time to rivals after an epic 246km of racing from Policastro to Serra San Bruno.
Battaglin, who rides for the Bardiani team, surged out of a small group of survivors from the day's second and last climb to sprint to a well-earned victory after nearly 6hr 15min of racing to the southernmost point of the Giro's 96th edition.
Minutes earlier, Danilo Di Luca, the Giro winner in 2007, belied his 37 years to launch an audacious attack on the final kilometres of the second and last climb and race into the lead with young Colombian Robinson Chalapud.
The pair came over the summit with barely 20secs on the main peloton but, despite Di Luca's efforts on the rain-hit finale, the pair were agonisingly caught inside the final kilometre.
Katusha veteran Paolini, who took the race lead with victory on stage three on Monday, was just behind and crossed the finish line in the company of overall victory hopefuls Vincenzo Nibali, Cadel Evans and Ryder Hesjedal.
Main race favourite, Team Sky leader Bradley Wiggins, however, lost time in the final kilometres to three key rivals.
Tour de France champion Wiggins was held up by a crash involving Italian Cristian Salerno on the approach to the final kilometre. Race rules normally dictate that riders caught up in such incidents in the final three kilometres are not penalised.
However the race jury said after the stage that Wiggins had not been hindered by the crash, thus attributing him with his initial finishing time.
Wiggins began the race's second-longest stage in second place overall at 17s.
But after a dominant display of riding by his Sky team on the 12.8km climb to the Croce Ferrata summit and, notably, the treacherous 7km descent to the finish, he has lost time to rivals which could prove costly.
Former Tour of Spain winner Nibali (Astana) turned his 14sec overnight deficit to Wiggins into a three-second lead, while both Hesjedal and, notably, Evans, also claimed back lost time.
Paolini now leads another Team Sky rider, Colombian Rigoberto Uran, by 17s with Nibali at 31, Hesjedal and Wiggins fifth and sixth respectively at 34 and Evans sitting 10th at 42.
Wednesday's fifth stage is held over 205 km from Cosenza to Matera and, although mainly flat, it ends on an uphill which will suit the 'punchers' and other specialist climbers of the peloton.