The British Grand Tour star kicked clear of the general classification favourites in the final kilometres of Monte Zoncolan on stage 14, with only maglia rosa Egan Bernal able to follow.
Bernal (Ineos Grenadiers) still came out on top, countering Yates (Team BikeExhange) and extending his overall lead, but Yates was still able to propel himself to second overall by the summit.
Yates was coy after the finish, but did hint that his quiet first week of the race was down to some sort of problems, which he preferred not to delve into.
Winner of the 2018 Vuelta a España Yates said: “I won’t go into detail, but It wasn’t the best of the first weeks and now I’m feeling much better, so onwards and upwards.
“Legs are getting there. Slowly but surely. Bernal showed he’s the man to beat. It’s going to be difficult to beat him but we’ll keep trying.”
The 28-year-old had made it through the first week of the Giro without any disastrous time losses, but was uncharacteristically reserved in the bunch, holding off on his usual ambitious attacks.
Yates’s tactics prompted many into believing it may be part of the BikeExchange tactics for their GC leader, keeping holding Yates back until the final week.
But Yates’s comments after the stage may instead hint an issue with form or illness during the opening week.
He now sits second overall in the 2021 edition, 1-33 behind Bernal.
Yates famously lost the Giro d’Italia back in 2018, after leading the race for two weeks following a number of huge attacks, before he dramatically fell out of contention with just one mountain stage remaining.
Since then, he has won the Vuelta and has tried to adapt his Grand Tour racing style, riding more conservatively to save energy deeper into a three-week race.
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