The 24-year-old Frenchman soloed away from his breakaway companions with a little more than 1km to go on the steep cobbled climb to the finish, and he quickly established his winning advantage over Giovanni Visconti (Bahrain-Merida) and Mattia Cattaneo (Androni Giocattoli). The two Italians rounded out the final podium, with Vincenzo Nibali (Astana) in fourth at 14 seconds and Colombian Egan Bernal (Androni Giocattoli) in fifth at 16.
Martin now has three stage wins and two overal victories since mid-August, starting with his stage win at the Tour du Limousin and continuing with a stage win and final overall victory at the Tour du Gevaudan last week.
"After my first victory in the Limousin, I made a click," Martin said. "When you start winning, you strive for victory again. It's a combination of the mental and physical aspect, because I've made enormous progress since the Tour de France.
"It is often said that you can push a gear extra, which is true, especially at my age. Then when the team takes me as a leader it gives more confidence. The whole team supports me and brings me in front at the foot of the climbs."
On Wednesday, Martin was part of the escape that formed on the final lap of the circuit around Volterra. When Visconti attacked with just over 3km to go, only Martin, Anthony Delaplace (Fortuneo-Oscaro) and Cattaneo could follow. The lead quartet approached the base of the final climb with an advantage of 40 seconds over the main peloton, which featured Nibali, Bernal and Cummings.
"The team brought me well in the run-up to the final climb, where Gasparotto accelerated at the foot," Martin said. "I followed him with four riders, but the climb was ridden tactically because it was not a very steep climb. When a group returned with Minnaard I immediately accelerated, so Visconti and I were in front. At one point, he did not want to take over and then I decided to attack again."
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Martin took the stage win by 10 seconds over Visconti and 13 over Cattaneo. More importantly for the overall, Cummings finished in a group more than 13 minutes back.
"After the differences of yesterday, I did not expect to win the overall ranking," said Martin, who started the final stage 25th overall in a large group of riders 12 seconds back. "But even with such big names at the start I knew that I could compete with them."
Martin will now turn his attention to finishing off his season with a series of one-day races starting on Thursday with the Coppa Sabatini-Gran Premio citta di Peccioli, the Giro dell'Emilia on Saturday and the Famenne Ardennes Classic in Belgium on October 11.
"I'm already thinking of the Giro d'Emilia, which fits me with its hard course," Martin said. "But I'm not planning to go easy this Thursday in Coppa Sabatini because at the end of this three-day Italian races there is a points classification in which I am currently in the lead. We will ride for [Andrea] Pasqualon tomorrow, and I want to get some points. Then I will finish the Italian week and finish my season in the Famenne Classic."
