With seven kilometres to go, four-time Tour de France winner Chris Froome attacked on the climb, and only a select group - Thibaut Pinot, Domenico Pozzovivo, and Bennett - were able to hang onto his wheel.
The quartet held their gap to the chasing pack for a few kilometres before they were caught on the descent, at which point Pello Bilbao attacked, opening up a gap which he wouldn't relinquish on the short uphill sprint to the line.
Bilbao came home six seconds ahead of Astana teammate Luis Leon Sanchez and Colombian Ivan Sosa, with Bennett in the next group along with his earlier companions, 10 seconds back.
None of the three riders who gained time gaps on Bennett are likely to be general classification contenders, with only a select few riders likely to be able to stay with the leaders on tomorrow's decisive stage, which ends in a gruelling mountain-top finish.
That will be the most telling test of Bennett's form, with the 28-year-old having already finished 11th, ninth and sixth in his three World Tour stage races so far.
While the Tour of the Alps is below World Tour level, it still possesses a handful of elite climbers, and if Bennett can be in the mix again tomorrow, it will be another positive sign as he ramps up for the Giro in just over two weeks time.
