Slovakian champion Peter Sagan continued his impressive start to his Tour de France debut with his second stage win inside three days on Tuesday.
RadioShack's Fabian Cancellara of Switzerland retained the overall leader's yellow jersey at the end of a crash-marred day which witnessed the race's first abandons.
Despite the near incessant drama on the tight, hilly roads leading to France's number one fishing port, plenty was kept in reserve for the last of six punchy climbs on the 197 km stage from Orchies.
Having sprinted to victory on an uphill finish on Sunday to open his Tour stage account, Sagan produced another display of power to finish ahead of Norwegian Edvald Boasson Hagen and fellow Slovak Peter Velits.
Amid a breakout season which has seen him win multiple victories at the Tour of California (five) and Tour of Switzerland (four), Sagan said he was simply sticking to his plan.
"After my wins in California and Switzerland I hoped to come here and win a few stages," he said, after also reinforcing his lead in the points competition for the green jersey.
"Now it's done and I'm very happy.
"Today I knew the sprinters wouldn't be there at the finish and it ended up with (Ivan) Basso and (Vincenzo) Nibali working for me!
"I would shine Basso's shoes if he asked, so I really can't say thank you enough to him."
There was no change to the top five overall, with race favourite Bradley Wiggins of Team Sky in second at 7sec behind and Australian Cadel Evans of BMC still 17 off the pace.
However Wiggins' Sky team were left having to "regroup", according to team principal Dave Brailsford after they lost Belarusian rider Kanstantsin Sivtsov to a crash.
He became the first of the 198 riders to abandon, leaving Wiggins a man down well before the race hits the crucial mountain stages.
"It's a setback, but not a devastating setback," said Brailsford.
"He'a a very good climber so he can do that first part in the key mountain stages. But to be honest the climbing department, as it were, is probably where we're at our strongest.
"It's a real shame, but not the end of the world.
"It's like boxing -- as long as you're still fighting you can knock the other fella out. That's the approach you've got to take to it."
Sky and many other teams will be glad to have limited their losses on a day that many had feared would take a toll.
Garmin sprinter Tyler Farrar and Spaniard Pablo Urtasun (Euskaltel) came down in the same crash which took out Sivtsov, leaving many to scramble over grass verges with their bike in a bid to get moving.
More drama followed soon after when Spanish sprinter Jose Joaquin Rojas (Movistar) crashed out of the race.
Australian champion Simon Gerrans (Orica-GreenEdge) flew over his handlebars while Italian Giampaolo Caruso of Katusha was caught up in the same spill.
Frenchman Sylvain Chavanel went on the attack in the closing stages and the Omega-Pharma rider briefly became the race leader before being reeled in by a chasing peloton with 450 metres to go.
Sagan, who had done well to stay in the front of the pack, then pounced in the final 300 metres to go on and seal victory.
Brailsford, lamenting Boasson Hagen's runner-up place, could only watch and admire.
"Sometimes it's like watching Messi play football, you just tilt your hat and say 'Chapeau'," added the Team Sky chief.
"He positions himself well and he deserves credit for it."
Sagan, meanwhile, said his teammates had given him a pre-race challenge.
"My teammates asked me to be like Forrest Gump. When you tell him to run, he runs. When they tell me to win, I win," said Sagan, who explained his gesture at the finish line.
"I always like to produce a good performance for the watching public.
"I've wanted to do that since since watching sport as a kid when my big hero was (motorbike racer) Valentino Rossi.
"I like to provoke the same feeling."
