With the sun shining over the Ardennes forests, and rain holding off until after the finish, Hamilton took the chequered flag two seconds ahead of Rosberg in Mercedes’ seventh one-two in 11 races.
What drama there was unfolded behind them, with Ferrari’s Sebastian Vettel lucky to escape unscathed from a 300kph blowout on the penultimate lap that robbed him of third place in his 150th grand prix.
Instead, Frenchman Romain Grosjean completed the podium for troubled Lotus.
“Today was a dream and the car was fantastic all weekend,” declared Hamilton, who controlled the race from the opening lap — after an aborted first start — and never looked threatened by his German rival.
“I was never in a position where I felt nervous, I had great pace in the car. There was no real need to push more than I had to,” he added.
The two collided at Spa last year, with Hamilton having to retire, but the risk of that happening again receded when Rosberg made a slow getaway off the front row and fell to fourth after the first lap.
“I just completely messed up the start,” said the German, who had hoped to capitalise on changed starting procedures that leave more to the driver and prevent engineers from helping remotely.
“Lewis did a great job, he deserved to win.”