Italy's Filippo Ganna gave the Ineos team a boost on Wednesday with a breakaway win in the fifth stage of the Giro d'Italia through the southern Calabria region with Portugal's Joao Almeida tightening his grip on the leader's pink jersey.

Ineos lost their lead rider Geraint Thomas to a broken pelvis on Tuesday, and subsequently promised to target stage wins instead of the overall standings.

"A success that partially redeems the team after Thomas's unfortunate retirement," said 24-year-old Ganna after his second stage win in this year's race.

It was also the time-trial specialist's first ever win on a raod race and given his huge frame, is an astonishing result for a stage where a slender climber had been expected to triumph. Ineos had a disappointing Tour de France with defending champion Egan Bernal's withdrawal, while Ecuadorian Richard Carapaz is not defending his Giro d'Italia title. The powerfully built world time-trial champion Ganna crossed the line alone 34sec ahead of a group of favourites including Deceuninck's Almeida, who finished third just behind Austrian Patrick Konrad of Bora-Hansgrohe. 

Ganna won Saturday's opening time-trial in Palermo, and on his first Giro d'Italia has two more time-trials to target. 

"It was not planned for me to go in the breakaway," said Ganna. "Then after some attacks this morning I told Salvatore (Puccio) to stay on my wheel. We managed to go in the breakaway, then all went incredibly well."

The race crossed to mainland Italy after four days in Sicily, covering 225km from Mileto to Camigliatello Silano. Ganna was the sole survivor of a breakaway launched before the 50km mark on the rolling slopes of the Valico di Montescuro, attacking with 17km to go. The Italian left Belgian Thomas De Gendt and Colombian Einer Rubio in his wake, after the pair had counterattacked at the foot of the climb, cresting the summit one minute ahead of his pursuers.

In the descent, uneven and slippery in the rain, Italian two-time Giro winner Vincenzo Nibali set the pace and tested his rivals. The Italian held on for the stage win, while his compatriot Nibali, winner in 2013 and 2016, remains  well positioned in sixth, one-minute adrift of Almeida.

"It was a very cold stage, with some rain," said Almeida who nevertheless extended his two-second overnight advantage to 43 seconds on second-place Spaniard Pello Bilbao. I'm happy with how I rode. After [Jonathan] Caicedo was dropped I managed to stay with the main favourites and gave everything until the finish line."

Thursday's sixth stage stays in the foot of Italy with a 199km run between Castrovillari and Matera in the Basilicata region.