Goals from Khvicha Kvaratskhelia and substitute Ibrahim Mbaye secured the win that put PSG beyond the reach of Lens in the Ligue 1 title race.
"Today, we spent more time defending than usual," said Luis Enrique.
"But if you want to win trophies, you have to be able to dominate both offensively and defensively. And the team today showed the mentality it needs to win."
PSG won the league with just one game to spare, a much tighter margin than in their 2024/25 campaign when they had the title wrapped up with six games left.
"This is the sweetest and hardest title to win. The hardest of the three years we’ve had here, without a doubt. But that’s also because Lens did a very good job," the Spanish manager said.
"And I remember certain moments from this season, the kind of matches they won and the number of consecutive matches they won. And it was tricky. We had to deal with that."
PSG face neighbours Paris FC in their final league game on Sunday, before taking on Premier League club Arsenal in the Champions League final later this month.