The midfielder swore on Twitter at a fan earlier in the week who accused him of not putting in maximum effort, causing negative headlines in the national Brazilian press.
He is currently on loan at Sao Paulo, a deal which expires at the end of the season, with his Arsenal contract remaining until 2014.
Last season he was hugely successful, part of the club's Copa Sudamericana winning side, but this campaign so far he has not enjoyed the same success with Sao Paulo in continental competition already losing three of their opening five Copa Libertadores group stage games.
They are however top of the league, winning again last night against Sao Barnardo 2-1, but made the tie a lot closer than it needed to be by virtue of a ridiculous own goal from Denilson.
You can watch it below... It does not look too bad from the first couple of angles, but when you see the third replay thirty seconds in and how the ball richochets from the inside of his knee into his own goal, you wonder just what exactly he was doing...