No. Nainggolan is.. not smart. And that is putting it mildly. But he is a very dedicated football player and a true professional. I don't think he set out to hurt anyone with that tackle and I still don't think it was even a foul.
Nainggolan is one tough motherfucker. In fact, if you and him were in the same room, you wouldn't talk like that, because he'd eat you alive. That being said he is not a dirty player. In fact he's anything but. Yes, he throws himself into challenges. But I've rarely, if ever, seen him do something malicious. In this case Mattiello came in far more recklessly.
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I'm not sure if he could have outmuscled him from that angle though. Tackling was a logical choice in my opinion.