Valerio Conti moved into the overall lead of the Giro d’Italia and Fausto Masnada won the stage as a long breakaway lit up the race on a day the maglia rosa hit the deck and dropped out of the top 10.
That early crash for leader Primoz Roglic set the tone for the long 238km stage, with the Slovenian's Jumbo-Visma team then content to sit in, control the main GC contenders, and give the breakaway sufficient leeway on a lumpy day in central Italy.
Italian duo Conti and Masnada worked together with gusto after zipping clear of the break on the day's big climb, heading into the finishing straight with both riders set to achieve their objectives.
Watch - Masnada claims maiden Grand Tour stage as Conti takes pink
Either way, the host nation were assured of a first win on the 102nd edition of La Corsa Rosa – and it was Masnada (Androni Giacattoli-Sidermec) who had the form to take a maiden Grand Tour stage win five seconds clear of Conti (UAE Team Emirates) who moved into the pink jersey with ample breathing room at the top.
Conti now holds a 1'41" lead at the top of the pack over compatriot Giovanni Carboni of Bardiani-CSF, who took fifth place on the stage to move into the lead of the white jersey youth classification and give the host nation a near clean-sweep of all jersey competitions.
Roglic, his backside bruised but ready to fight another day, came home in the bunch, dropping down to 11th in the standings. He now trails Conti by 5'24" but maintains his 35-second lead over major GC threat Simon Yates (Mitchelton-Scott).
Conti - It's a dream come true to wear the pink jersey
Stage 6: Cassino to San Giovanni Rotondo - as it happened
Sunshine returned to the race as the riders rolled out of Cassino for the second longest stage of the race. But things did not start brightly for the race leader Roglic, who came down in a crash that also affected his GC rivals Rafal Majka (Bora-Hansgrohe), Mikel Landa (Movistar) and Ilnur Zakarin (Katusha Alpecin).
The incident occurred towards the end of the first hour of racing as a lead group of six riders were being pegged back after failing to establish a lead that stuck.
Roglic required treatment to his right buttock, which became cruelly exposed to the elements with 200km still remaining. But the damage did not seem lasting, with the Slovenian soon back on the front of the pack alongside his Jumbo-Visma team-mates as the peloton controlled the lead of a 13-man move which formed on the second of a series of uncategorised climbs.
The break – José Joaquin Rojas and Andrey Amador (Movistar), Nans Peters (Ag2R-La Mondiale), Pieter Serry (Deceuninck-QuickStep), Ruben Plaza (Israel Cycling Academy), Nicola Bagioli (Nippo-Vino Fantini-Faizanè), Valerio Conti (UAE Team Emirates), Fausto Masnada (Androni Giacattoli-Sidermec), Giovanni Carboni (Bardiani-CSF), Valentin Madouas (Groupama-FDJ), Sam Oomen (Team Sunweb) and Amaro Antunes (CCC Team) – built up a lead of 4’25” with 150km remaining as the sun gave way to persistent drizzle.
Trailing Roglic by 1’59” going into the stage, the Italian Conti was riding as virtual maglia rosa in a strong move which looked a safe bet of going all the way to the finish.
Flying the flag for the Dutch and Team Sunweb – in the absence of the 2017 champion Tom Dumoulin – was the young climber Oomen, sporting a cut on his chin after being caught up in the earlier Roglic pile-up which also forced out his team-mate Rob Power, reducing Sunweb to just six riders.
The gap steadily grew to above the six-minute mark with 100km remaining, the Jumbo-Visma squad of the maglia rosa content to keep a lid on things without leading any ostensible chase.
Crosswinds in an exposed plain on the flat run towards the foot of the day’s major climb momentarily split the peloton as the gap started to slowly fall. But the excitement did not last long and there was an element of stalemate as the race continued towards the foot of the biggest climb so far of the 102nd edition.
With a gap of just over five minutes, the 13-man move edged onto the early slopes of the Cat.2 climb of Coppa Casarinelle – its relatively gentle average gradient of 4.4% over 15km hardly pulverising, but a difficult test nonetheless after more than 200km already in the saddle.
Masnada put in the first big attack and was joined by Conti as the two Italians build up a good gap over a trio of chasers in Plaza, Rojas and Carboni. Masnada, who won two stages in the Tour of the Alps in April, took maximum points over the summit before Conti pocketed three extra bonus seconds at the subsequent intermediate sprint.
The understanding between the two Italians was strong – especially with Conti in line to snare the maglia rosa at the end of the stage. For the gap back to the peloton – being led with apparent indifference by Roglic’s Jumbo-Visma team – was now well over seven minutes. Stage win or not, Conti was looking at a five-minute lead over Roglic at the top of the new-look general classification.
With 10km remaining, the duo held a 30-second gap over the three chasers with Oomen leading a second group of six a further 15 seconds back.
Guaranteed a maiden stage-race leader's jersey of his career, Conti led Masnada on the home straight before the latter kicked clear to take the biggest win of his career and his wildcard team's first on the Giro since 2012. The 25-year-old also moved within six points of compatriot Giulio Ciccone (Trek Segafredo) at the top of the maglia azzura standings.
Rojas pipped fellow Spanish veteran Plaza for third place at 38 seconds with Carboni, the new white jersey, completing the top five.
The remnants of the break arrived in drips and drabs before the peloton rolled home 7'19" in arrears after an attritional day in the saddle.
Friday's stage 7 is a 185km ride from Vasto to L'Aquila which includes more rolling roads and another tough second-category climb before the finish. Ideal breakaway territory for anyone wishing to take a leaf out of Conti and Masnada's book.