The Dakar legend came home victorious by just under 42 minutes in Lima , with X-raid Mini team-mate Nani Roma second and Giniel de Villiers third in a Toyota.
Peterhansel admitted that having not won since 2007, and having passed his 46th birthday, he was wondering if he had scored his last Dakar triumph.
"When you think of how hard it is to win a Dakar, it's incredible that I've been able to win 10 of them," said Peterhansel. "It's been a long time, I've been waiting for five years to win again!
"To take the victory in South America is a huge relief, it ranks among my best triumphs. Moreover, the race was very close during the first week and there was always a lot of pressure. Winning the rally for Team X-raid makes it even more special, since Sven Quandt has been waiting for years for this to happen.
"I don't know what I could do to go one better! Beating this record is going to be difficult... for the others!
"My finest victory will always be my first win in the motorcycle category, but this one has something special to it. I was starting to doubt myself, to think I was growing too old for this, that I'd lost it or that I wasn't made for South America... and in the end everything turned out fine."
The Hummers of Robby Gordon and World Rally driver Nasser Al-Attiyah looked to have the speed to challenge Peterhansel at the front, but had too many issues and incidents, with Al-Attiyah retiring and Gordon ending up fifth - a result he may yet lose if an appeal against exclusion for an alleged technical non-compliance is not successful.