"I have the legs to win now, so we celebrate tonight and maybe the same tomorrow", Groenewegen told reporters after the stage.
Peter Sagan thrust his arm and fist forward like Superman.
While they fought back to join the chase group, a third group led by Lotto and their rider Primoz Roglic struggled to stay in touch.
With almost six hours in the saddle and hardly any action until the finale, there was plenty of time to relax and fool around during the longest stage of the Tour de France on Friday.
Dumoulin and Bardet entered the three-week race among the chosen few riders considered strong enough to challenge four-time champion Chris Froome.
"It was a pretty calm day [on stage 7 on Friday], but you still had to be focused as guys tried twice to force echelons and that made it kind of nervous". But it was boring.
"I'm happy with that, " Sagan said.
"I knew I wouldn't make it back so it was about limiting the time loss", Dumoulin said.
"Third is okay, if I win what do I get except an extra point or two?"
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On Thursday night, he notched his third consecutive double-double in a 15-point, 12-rebound game against the Atlanta Hawks. Jackson had 13 points, six rebounds, one assist and a steal for the Pelicans in 13 minutes of play before being sidelined.
Halfway through the stage, the AG2R-La Mondiale, Trek and Movistar teams accelerated in crosswinds and caused splits in the peloton, with Irishman Dan Martin, one of the overall contenders, trapped behind.
Froome is 14th, 1:05 behind Van Avermaet. "It was good to finish second back then but this time I was coming for victory", Martin said.
"I had a good day", said the Slovak, who has, like Gaviria, two stage wins so far.
Sagan would regret going as early as he did as he faded in the final 100 metres and finished fourth.
After crossing the line, Groenewegen placed his finger to his lips in a gesture of silence. I went with 200 meters and it was good enough.
The Dutch cyclist, who rides for Team Lotto NL-Jumbo, clocked almost six hours over the 231-kilometer (143.5-mile) trek from Fougeres, home to the best-preserved and largest medieval fortress in Europe, to Chartres, site of a vast cathedral known for its stained-glass windows. But what do the full standings at the 105th edition of the Tour look like after eight days of racing? "You can ask the question, is this really necessary in a Grand Tour?"
Belgian Greg Van Avermaet retained the leader's yellow jersey ahead of Saturday's eighth stage and said he hope to go to the mountains with it next week after what he described as a relaxing day.
Instead, it was Yoann Offredo of Team Wanty-Groupe Gobert who led on his on his own for around 80km.
Laurent Pichon, another French rider with Fortuneo-Samsic, then also got away alone for a spell. The break was therefore given little leeway and despite a brief late attack by Philippe Gilbert, a bunch sprint was all but inevitable. "The stage into Roubaix on Sunday is the last technical point in the first part of the race".