Both sides seemed to lack the cutting edge through much of the match, with even Mbappe misfiring as the club struggled bit without the services of Neymar, Edinson Cavani, Marco Verratti and Thomas Meunier.
But the French star came up with the moment of magic in the 73rd minute, guiding Dani Alves's lofted pass into the top corner on the volley to score his 19th league goal of the season.
And the 20-year-old says his strike was just proof that persistence pays off, having missed a similar chance earlier in the contest.
"I tried a first time, I sent it over the top, in the stands," he told Canal+. "But when we persevere, it pays.
"[Alves] gave it perfectly to me at the right time and I played it instinctively."
The goal and the win pushed PSG's lead at the top of Ligue 1 to 12 points, the club having lost just once so far this season, and their star man was pleased to pick up another victory in tricky circumstances.
"We played against a good team," he said. "They play with the heart, and try to play ball also.
"Not many teams will win here. We are happy.
"That's good, we must continue. We must aim as high as possible."
Mbappe was once again named as the star performer of the night, but the forward says he would rather have team success, though he did admit to enjoying adding to his personal trophy case.
"The personal stats are good, but the collective is better," he said. "Individual trophies, I have quite a lot right now at home, but there will never be enough."