The 2019 Tour de France winner was the main aggressor of the final climb of Ascoli Picento, attacking with two kilometres left to climb on the 15 kilometre final ascnet and shedding rivals for the final victory in Milan en route to the peak of the climb.
Gino Mäder (Bahrain Victorious) won the stage from the early breakaway, finishing 12 seconds ahead of Bernal, who sprinted all the way into the line to secure more time on his rivals and the bonus seconds on the line for second place on the day.
Dan Martin (Israel Start-Up Nation) nearly overhauled Bernal but finished third, with Remco Evenepoel (Deceuninck-QuickStep) and Giulio Ciccone (Trek-Segafredo) following in behind on the same time.
Damiano Caruso (Bahrain Victorious) and Daniel Martínez (Ineos Grenadiers) were next across the line, losing 13 seconds to the Bernal group. Marc Soler (Movistar) lost two further seconds to finish 27 down on Mäder, while Hugh Carthy (EF Education-Nippo), Aleksandr Vlasov (Astana-Premier Tech), Simon Yates (Team BikeExchange) and Attila Valter (Groupama-FDJ) were a further two seconds back.
Valter's impressive ride to 12th on the stage secured him the maglia rosa, the 22-year-old is the first Hungarian to hold the race leader's jersey in the Giro's 104-year history.
The result leaves Evenepoel as the top-placed GC candidate in second overall after a strong time trial, 11 seconds down on Valter. Bernal lies third overall, 16 seconds adrift of the young Hungarian.
Australian Jai Hindley (Team DSM) was runner-up last year at the Giro d'Italia, but has yet to show that same form in the early climbing stages. The West Australian was well-positioned by the work of fellow Aussie Michael Storer on the final climb, but dropped off the pace with over two kilometres left to race, ceding two minutes and 26 seconds to the Bernal group and leaving Hindley 25th overall, three minutes and 29 seconds behind Valter.
Hindley's teammate Romain Bardet (Team DSM) may have taken over the sole team leadership after the stage, with the Frenchman finishing just 28 seconds behind the Bernal group and sitting just a minute and 14 seconds behind the race lead.
Bernal was the one that everyone talked about post-stage, with the Colombian climber explaining the strategy coming into the first summit finish of the 2021 Giro.
“The original plan was to not lose time in what was the first test in a longer climb," said Bernal, "we weren’t sure how the legs were going to be, we were going to be conservative but anyway, during the race we realised that we were feeling good, it started to rain and we wanted to be at the front.
INEOS Grenadiers applied a lot of pressure on the plateau after the first ascent of the stage, splintering the peloton and consigning race leader Alessandro de Marchi (Israel Start-Up Nation) to a short stint in the leader's jersey as he was dropped by the surge.
"There was a moment in the race where there was the opportunity for us to control the race, we had the idea to take the opportunity where we knew there was going to be winds at a certain point," said Bernal. "I think it was an aggressive race, in the end with the headwind, people in the wheels were able to conserve some energy, so the strategy wasn’t quite as successful, but anyway it all worked out, we didn’t lose any time, a few seconds with a couple of our riders, but we’re taking it bit-by-bit."
The 2021 Giro d'Italia continues with Stage 7, a 171-kilometre stage from Notaresco to Termoli. The second half of the stage runs along the Adriatic coast and could be the first big chance for crosswinds in the race. Watch on SBS OnDemand from 2040 AEST, with the SBS VICELAND broadcast starting at 2120.