Asked if it would be a battle all the way to Paris with Fernando Gaviria for the green jersey prize, Sagan said: "I hope not!"
"I had a little coming together with Alex at the end, it might've been my fault but it just stopped me dead".
"I have my own style", he said when asked about his similarity to the veteran Manxman with 39 stage wins under his belt.
Gaviria and Slovakia's world champion Peter Sagan would end second and third on the same time as the victor. I'm really grateful. I was behind Kristoff and he was going, I stayed in is wheel and thought now is the moment.
After winning such a prestigious stage to conclude last year's Tour, Groenewegen struggled to make an impact in the early days of this race, a fourth-place finish in Stage 4 his best effort until this victory, which he feels will kickstart his race.
It's not a day that should affect the General Classification, as overall leader Greg Van Avermaet should have no trouble with the finish. I think I went too early in the sprint.
Belgium's Greg Van Avermaet, of BMC, retained the overall yellow jersey, while Briton Chris Froome, of Sky, the defending champion, is one minute and two seconds off Van Avermaet's overall lead.
Today he certainly made good on his threat.
Sagan victory hints at further improvement
The stage, the longest of this year's Tour, was ridden at such a serene pace at times it might have been mistaken for the first rest day.
"It was a boring stage, no wind, no stress just boring, I was talking to everybody", he said.
"People had been saying I was not good enough to win a stage on this Tour, so I put my finger to my lips to tell them to shut up", said Groenewegen, explaining his gesture at the finish line.
"I'd like to thank Greg (Van Avermaet) because he did me a favour when he went for it, I don't know if he did it on objective but he dropped a lot of people", said Sagan, who has tightened his grip on the points classification's green jersey.
Laurent Pichon, another French rider with Fortuneo-Samsic, then also got away alone for a spell.
Stage eight on Saturday (Sunday NZ time) covers a slightly more challenging terrain over 181km from Dreux to Amiens but again should set up well for sprinters.
It was in 2011 when the Tour first finished a stage on the steep, two-kilometre climb to Mur-de-Bretagne.
The upcoming seventh stage runs from Fougeres to Chartres.
Chelsea ace Hazard warned he's only backup in Real Madrid transfer plans
And the 24-year-old has not been told by Juventus about whether he remains in Massimiliano Allegri's plans alongside Ronaldo. Former Juventus player Alessandro Del Piero has hailed the £100million arrival of Cristiano Ronaldo from Real Madrid .