Dennis, the Australian riding for BMC Racing, produced an imperious performance to lead through both intermediate time checks.

He completed the 34.2 kilometres course in a blistering time of exactly 40 minutes to win on the day by 14 seconds from Germany's four-time world time trial champion Tony Martin, who was riding for Katusha-Alpecin.

The Netherlands' reigning world champion Tom Dumoulin finished third, 22 seconds behind Dennis, to remain second overall.

Mitchelton-Scott's Yates had led the Team Sunweb rider by 2:11 at the start of the day.

The Briton remained 56 seconds ahead after a respectable time of 41:37 in an event seen as his weakness.

Three more summit finishes are still to come, which would favour Yates' climbing prowess so long as the rigours of the final week of a Grand Tour do not catch up with him.

Bahrain-Merida's Domenico Pozzovivo remains third but slipped 3:11 off Yates' pace after losing more than two minutes on Dennis.

Team Sky's Tour de France champion Chris Froome moved up to fourth, just 39 seconds off third, after crossing 35 seconds after Dennis in fifth today.

Dennis now lies sixth overall, one place behind France's Groupama-FDJ rider Thibaut Pinot, who lost over three minutes today and was duly leapfrogged by Froome in the overall standings.

Action is due to continue with a 155km stage from Riva del Garda to Iseo tomorrow.