Tour de France 2015: Ruben Plaza triumphs on stage 16 as Geraint Thomas overcomes huge crash to finish 38 seconds behind

Peter Sagan was left disappointed again

Peter Sagan was left disappointed once again as Spaniard Ruben Plaza triumphed on stage 16 of the Tour de France to Gap on Monday.

Slovakian Sagan (Tinkoff-Saxo) was among the day's main protagonists, but had to settle for second for a fifth time in this year's Tour - and a 16th time in all - as Plaza (Lampre-Merida) won on the 201-kilometres route from Bourg-de-Peage.

The main contenders rolled in 18 minutes 12 seconds behind as Chris Froome (Team Sky) maintained his lead of three minutes 10 seconds over nearest challenger Nairo Quintana (Movistar).

But there were concerns for Team Sky, for whom Geraint Thomas was knocked off the road on the defence after being nudged accidentally by Warren Barguil (Giant-Alpecin).

Thomas, who began the day sixth overall, flipped over his handlebars near a telegraph pole, tumbling off the road, but recovered to finish 38 seconds behind the Froome group.

Reports off the bike, meanwhile, suggested Sir Dave Brailsford was considering releasing performance data to support his defence of Froome after the Team Sky principal was ambushed by the Tour's host broadcaster on Sunday.

Froome's performances have been closely scrutinised, particularly his win to La Pierre-Saint-Martin, and France 2 broadcast its own expert analysis after the 15th stage to say the 30-year-old had an "abnormally high" power profile.

Team Sky may choose to address the ongoing insinuations on Tuesday's rest day, insisting Froome is a clean athlete, but Brailsford has always stated it is not possible to prove a negative, that Froome is drug free.

Plus, any data release could invite more questions than answers for a media and public sceptical after years of drug-riddled performances at the Tour.

Greg van Avermaet (BMC Racing), who won the stage to Rodez ahead of Sagan last Friday, did not start as his wife is to give birth imminently.

The peloton was soon reduced to 169 riders as Pete Kennaugh (Team Sky) abandoned following illness, depriving Froome of a key lieutenant for the forthcoming Alpine stages, which begin on Wednesday.

Racing was extremely fast due to a tailwind and numerous riders tried to make the day's breakaway, desperate to seize a potentially final chance to take a stage win before four days in the Alps and the ceremonial finish in Paris on Sunday, which is likely to conclude in a sprint.

Two large groups formed and eventually converged in a bunch of 23, with Sagan present alongside Edvald Boasson Hagen (MTN-Qhubeka), who were both among the favourites for the stage.

The peloton, led by Team Sky, was more than 12 minutes adrift and drifting further behind as first Adam Hansen (Lotto-Soudal) attacked.

The Australian, riding in his 12th successive Grand Tour, has struggled through injuries from a first-week crash and clearly was feeling stronger.

His advantage was slender with around 40km to go, but he was wearing a skinsuit in order to gain an aerodynamic boost.

He was soon joined by Austrian Marco Haller (Katusha) and the pair had an advantage to one minute at the foot of the second of the day's two categorised climbs, the category two Col de Manse.

The duo were caught midway up the 8.9km ascent as the counter attacks from a fractured chase group began, led by Plaza.

Sagan was prominent throughout, eager to improve on his four second-place finishes so far in the race, but even the flamboyant Slovakian was struggling to reel in Plaza, who reached the summit one minute ahead.

Sagan risked everything on the descent in pursuit of a victory which instead went to Plaza.

Defending champion Vincenzo Nibali (Astana) and Alberto Contador (Tinkoff-Saxo) attempted to put Froome under pressure on the final ascent.

Italian Nibali gained 28 seconds on the Froome and Contador group, which only chipped marginally away at his significant deficit with five days' racing remaining.

PA