Plaza (Lampre-Merida) attacked the remnants of the day long break with just 11km to go and carried on to win solo as Sagan (Tinkoff-Saxo) employed all of his legendary skills in an attempt to win the 201km stage from Bourg-de-Péage to Gap for himself.
Third on the stage was IAM’s Jarlinson Pantano who more than matched Sagan during the high speed drop to the finish.
Once again there was no change to the general classification with Chris Froome (Sky) neutering a half hearted challenge from Alberto Contador (Tinkoff-Saxo) before letting Vincenzo Nibali (Astana) ride away to a small but insignificant time gain.
The stage was momentarily marred by a terrible looking crash involving Sky’s Geraint Thomas who was bumped off his line on the fast descent before crashing into a telephone pole. Concerns were high but he remounted to finish less than a minute behind his team leader Froome.
The winning break started with 12 riders and later swelled to 23 with Sagan an always active presence in his desperate search for a stage victory to add credibility to his green jersey exploits.
The Tinkoff-Saxo star added to his points classification lead with an uncontested win at the only intermediate sprint of the day before actively marking any dangerous looking moves for the remainder of the stage.
Also in the break, Australia’s Adam Hansen (Lotto-Soudal) and Marco Haller (Katusha) took a long range shot at victory, but with Sagan driving the pace the pair were caught with 18km to race.
Next cab off the rank was Plaza who quickly built a lead on the Sagan group approaching a minute at the top of the Category 2 Col de Manse.
From that point it was a game of cat and mouse, with Sagan doing the stalking and Plaza the defending.
In the end Sagan only managed to pull back 30 seconds as the 35-year-old Plaza finished with enough time in hand for the victory.
“It’s such an exciting victory, such a great success,” said Plaza after his first win of the season.
“In this Tour de France, we have been unlucky and we suffered for the withdrawal of our captain Rui Costa, who won here two years ago. We tried hard to hit an important target, we did not give up and we made a lot of attempts attacking or fighting in the sprints.”
Plaza’s first win at the Tour de France came as the result of careful teamwork matched by the two-time Spanish road champion’s ability to maintain his composure on the fast decent to the finish line.
“Today we achieved our goal,” he said.
“It’s always so difficult to win in the Tour de France, but today everything was in its right place and I added my good legs and my fighting spirit.
“I put everything in the attack on the Col de Manse and in the descent I try to keep my mind well focused on the road.
In my career I had obtained 22 victories, but today the feelings are so special.”