Cavendish burst off the wheel of Germany’s Marcel Kittel on the final straight in Montauban to move clear of Bernard Hinault on 28 and move within five of Eddy Merckx’s 34.
Etixx-QuickStep’s Kittel came in second, while finishing fastest of all was Dan McLay, the British Tour debutant who came in third to collect his fourth top-ten finish of his first Tour and best result yet.
Cavendish has enjoyed some outstanding Tours in his career, winning six stages in 2009, and five each in 2010 and 2011, but the 31-year-old has never before collected three wins in the first six days.
“Oh my god, that was terrifying,” the Team Dimension Data rider said. “That was like the old days, wheel surfing. I was a little too far back going into that so it was just carnage in the final. I wanted Kittel’s wheel and I was fighting for it.
“I knew it would be the right thing to go early because it was slightly downhill, I put the bigger gear on again but I maxed out and should have put a bigger gear on. I held Kittel off, I did to him what he’s done to me over the last three years.”
Cavendish’s win sees him move back to the top of the points classification ahead of Tinkoff’s Peter Sagan.
BMC’s Greg Van Avermaet finished safely in the pack to retain the yellow jersey he took on Wednesday.
Today’s Stage 7 offers the first taste of the Pyrenees,a 162.5km leg from L’Isle-Jourdain to Lac de Payolle featuring the legendary Col d’Aspin climb shortly before the finish.