But Tour de France champion Chris Froome, who won on Saturday’s Monte Zoncolan summit finish, lost more time on the 176km Dolomites stage from Tolmezzo to Sappada, slipping to seventh overall and nearly five minutes behind his countryman.
Mitchelton-Scott’s Yates launched his attack 17km from the finish line on the penultimate climb and held on to add to his previous victories on the ninth stage at Gran Sasso and 11th at Osimo.
He crossed the line 41 seconds ahead of a group led by Colombian Miguel Angel Lopez of the Astana Pro Team, with Team Sunweb’s Tom Dumoulin of the Netherlands in third.
“My attack was a little bit on instinct,” explained Yates. “I saw a little gap. I gave everything the second time to get away. It’s fantastic.”
Defending champion Dumoulin is second overall but drops to 2min 11sec behind Yates going into the final week with the race finishing in Rome next Sunday.
📸 Best pics from Stage 15, Tolmezzo - Sappada. Which one do you like the most? | 📸 Le migliori immagini della Tappa 15, Tolmezzo - Sappada. Qual è la tua preferita? | 📸 Las mejores imágenes de la Etapa 15, Tolmezzo - Sappada. ¿Cual prefieres? https://t.co/haOAnSRKxj#Giro101 pic.twitter.com/p0rJUQGEzU— Giro d'Italia (@giroditalia) 20 May 2018
Monday’s final rest day will be followed by a time-trial at Rovereto on Tuesday where Dutchman Dumoulin is expected to gain time.
“I feel emotional after today. I’ve been fighting since Israel to build a good lead,” said Yates.
“I’m happy with the gap I have now but it’s far from over. It could vanish in 35 kilometres.”
Italy’s Domenico Pozzovivo finished fourth and is third overall, 2min 28sec behind Yates, with France’s Thibaut Pinot of Groupama fourth overall at 2min 37sec.
Four-time Tour de France winner Froome struggled on the fourth and final climb in the Dolomites losing a minute and a half to spoil his 33rd birthday celebrations.
Froome, helped by teammate Wout Poels who had already proved so valuable on Monte Zoncolan, tried to claw back time on the overall leaders but was unable to match the change of the pace on the ascent to Costalissoio.
The reigning Vuelta a Espana champion dropped from fifth to seventh overall and is now 4min 52sec behind 25-year-old ‘King of the Mountains’ Yates.
But will Yates’ advantage be enough in Tuesday’s time trial? “I really don’t know,” he said.
France’s Pinot believes the Englishman has done the essential though.
“Yates is untouchable unless he has a major failure,” said Pinot.
“It was better than yesterday at the Zoncolan,” he added. “There are days like this … Today, the slopes corresponded more to me.”
But Pinot lamented a damaging battle between Lopez and Ecuadorian Richard Carapaz for the best young rider’s white jersey.
“There was the squabble between Carapaz and Lopez for the white jersey, they were eye-balling each other, they condemned our little group a little,” said Pinot, who is fourth overall just behind Pozzovivo.
“Maybe we could have caught up with Yates and especially taken time on the others,” added the Frenchman.
Britain’s Chris Froome won the 14th stage of the Giro d’Italia on Monte Zoncolan as compatriot Simon Yates extended his overall lead in the Alps.
With the peloton swiftly breaking up as riders tackled the grueling final climb on the 186km stage from Sanvito Al Tagliamento, Team Sky’s Froome surged clear to win by six seconds.
Mitchelton-Scott ‘s Yates was second – 31 seconds ahead of defending champion and nearest challenger Tom Dumoulin in the battle for the maglia rosa.
With six bonus seconds for finishing second, Yates extended his overall advantage to 1:24.
Great Britain’s Simon Yates still has a 47-second lead in the Giro d’Italia’s general classification after the 13th stage, which was won by Elia Viviani.
Italian Viviani (Quick-Step Floors) emerged victorious from a bunch sprint at the end of the flat, 180-kilometre run from Ferrara to Nervesa della Battaglia on Friday for his third stage triumph of this year’s race.
Sam Bennett (Bora-Hansgrohe), who on Thursday registered his second victory of the race to become the first Irishman to win two or more stages in the same grand tour event since 1988, was second behind Viviani, with Dutch rider Danny Van Poppel (LottoNL-Jumbo) coming third.
Yates (Mitchelton-Scott) and his closest rival in the general classification, Belgium’s defending champion Tom Dumoulin (Team Sunweb), both finished safely within the bunch with the same time.
Viviani, bouncing back after a disappointing Thursday as he added to winning stages two and three, is now 40 points clear of second-placed Bennett in the points classification.
Saturday sees the riders tackle a tough mountain stage, the 186km from San Vito al Tagliamento to Monte Zoncolan.
🇮🇹 @eliaviviani wins the stage in Nervesa della Battaglia! 🚴🚴🚴
What a sprint! 😍
— Unibet Belgium (@unibetbelgium) May 18, 2018