Thomas now leads by 1min 29sec in the overall standings as he seeks to continue British and Team Sky success at the week-long race.

It came on a 110 kilometres stage from Frontenex which is almost a carbon copy of this year's Tour de France stage 11.

Bibao, a Spaniard riding for Astana, attacked early on during the conclusive 12.7km climb.

He held on superbly to complete a solo stage win in 3 hours 34min 11sec.

Thomas crossed in second, 21 seconds behind.

Ireland and UAE Team Emirates' Daniel Martin, the winner of stage five yesterday, was a further two seconds back in third after outsprinting France's Ag2r La Mondiale contender Romain Bardet.

Mitchelton-Scott's Briton Adam Yates was 26 seconds behind the stage winner in fifth.

Thomas now leads Yates by 1:29 in the overall standings.

He is seeking to become the fifth British winner and follow recent successes for other Team Sky riders in Sir Bradley Wiggins in 2011 and 2012 and for Chris Froome in 2013, 2015 and 2016.

Bardet is another 32 seconds back in third, 29 seconds ahead of fourth-placed Martin.

An 18.3km team time trial in Frauenfeld also took place today to mark the start of the Tour de Suisse, another World Tour event.

With the exception of Froome, who is resting after his Giro d'Italia win last month, almost all the Tour de France contenders not racing at the Dauphiné are present.

BMC Racing took a predictable victory in the race against the clock to put Switzerland's Stefan Küng in the leader’s jersey.

An all-star team also including Australia's Richie Porte, American Tejay Van Garderen, and Belgium's Olympic road race champion Greg Van Avermaet clocked 20:18.

It gave them a 19 second lead over Team Sunweb and a 27 second advantage over Quick-Step Floors.