But Bennett stuck to his rival and just pipped the home favourite to the line to become the first Irish victor of a Giro stage since Stephen Roche in 1987.
On the 15 kilometre final climb on Mount Etna, Bennett was stronger than a huge array of pre-race favourites, shining brighter than the likes of Chris Froome, Tom Dumoulin, Fabio Aru and Miguel Angel Lopez.
"It was unbelievable to wear the pink jersey - something I was hoping for, but you never really expect it".
Dennis' defeat was far from decisive, however, as the rider bearing the maglia rosa since Tel Aviv in Israel on Stage 2 crossed the line a relatively minor 1:04 behind stage victor Esteban Chaves (Mitchelton-Scott).
He employed interesting tactics to claim the win, preferring to eschew his leadout riders for a spot on the wheel of big favourite, and two-time stage victor already, Elia Viviani.
Warriors favored over Rockets, who have home court
Game 6 of that series, if necessary, would be Friday in Philadelphia, with a potential Game 7 scheduled for Sunday back in Boston. The Warriors advanced past the Pelicans in five games, while the Rockets moved past the Jazz in five games.
Chaves, the last man standing from the break of the day, is another 10 seconds adrift of his colleague Yates, while Dennis finds himself with 53 seconds to make up after failing to react when the climbers attacked.
Yates added: "I felt really good, I looked across the road and everyone was looking at each other".
The Adelaide rider had led by one second for four days and he dropped to sixth overall.
Yates's second place on the stage was good enough for him to take the race leader's Maglia Rosa (pink jersey) off BMC's Rohan Dennis - who struggled on the first mountain-top finish of this year's race.
"They were really far back and I thought there was no way we'd come back because there was the chicane still to come and I thought for sure it would be one line so even if we did get back, would I still have the power still to go?"
Bennett is the first Irish victor of a Giro d'Italia stage since Stephen Roche in 1987.