The Toyota driver clinched the first gravel rally of the new Rally1 hybrid era by 15.2 seconds after seeing off a brief challenge from teammate Elfyn Evans.
Rovanpera sealed the victory in style by winning the final powerstage on the weekend where the WRC celebrated its 50th season.
Hyundai's Dani Sordo claimed the final podium position, following an intense fight with Toyota's Takamoto Katsuta that raged until the final powerstage, where the Spaniard overhauled his rival.
The pair had driven smartly throughout and were among a quartet of Rally1 drivers to avoid any issues over the four days.
The rally belonged to 21-year-old Rovanpera, who produced yet another flawless drive, with this latest victory perhaps the most significant to date given the disadvantage of having to act as road sweeper on the dusty stages on Friday.
While several of his rivals were hit by punctures and misfortune across a run of extreme rough gravel stages, Rovanpera emerged unscathed, notching up two stage wins to trail Evans by 13.6s in second.
The Toyota pair duelled for the top spot through Saturday with Evans extending his lead to 18.4s, before Rovanpera rattled off a pair of stage victories to take the lead on stage 15 when heavy rain fell.
Rovanpera managed to transform a 9.9s deficit into a 4s lead, adding further gloss in the day-ending Super Special.
Equipped with a 5.7s advantage heading into Sunday, Rovanpera swept to a fifth career WRC victory, claiming the five bonus powerstage points to extend his championship lead to 46 points over Hyundai's Thierry Neuville.
A first podium of the season for Evans arrived after twice leading the rally in what was his best drive of the season to date.
Evans moved into the rally lead on Friday morning after leap-frogging Neuville, who won Thursday's super special opener.
The Welshman then lost the lead on stage 4 to M-Sport's Sebastien Loeb, who sensationally leapt from seventh overall to the lead with a stage win.
However, Loeb made a rare driver error, sliding into a wall on stage 5, which caused terminal damage to the nine-time world champion's Ford Puma, forcing the Frenchman to retire.
Loeb briefly returned to the fray on Saturday before a loss of power put him out of the rally completely.
Fellow multiple world champion Sebastien Ogier rose to third following Loeb's retirement before becoming among the victims to suffer issues on the rough tests.
The Toyota driver suffered two punctures in consecutive stages, which forced the eight-time world champion into retirement after electing to carry only one spare wheel.
Ogier retired again on Saturday when he crashed out on stage 11 after being distracted by his dashboard following a hybrid issue on his GR Yaris. The Frenchman returned on Sunday to compete the final five stages.
Neuville was also among a group of drivers who witnessed a podium chance slip as the Belgian was left to settle for fifth overall after driveshaft failure dropped him from second position on Friday afternoon.
Hyundai teammate Ott Tanak recovered to sixth overall after a double puncture on Friday dropped the 2019 world champion from fourth to 10th spot.
Pierre-Louis Loubet emerged as the best M-Sport Ford driver in seventh although the Frenchman had run as high as fourth before a wild off on Friday evening.
Craig Breen ended a difficult rally in eighth after losing time to a puncture on Friday followed by a poor tyre call on Saturday and a brake issue on Sunday.
Adrien Fourmaux was ninth having lost three minute to a puncture on Saturday, while his M-Sport teammate Gus Greensmith also suffered from tyre issues before returning to the rally on Sunday after suspension damage put him out of action on Saturday.
