Newcastle United manager Steve McClaren has urged striker Aleksandar Mitrovic to keep playing on the edge, but warned he must be smart in doing so.
Mitrovic was a £13million signing from Anderlecht in the off-season but his aggressive style of play has come under scrutiny.
The Serbia international picked up a yellow card seconds after making his debut for the club, before being shown a straight red in Newcastle's 1-0 loss to Arsenal in August.
However, the 21-year-old has turned things around, scoring two goals in his past two games against Manchester City and Norwich City respectively, without picking up any yellows.
Ahead of Sunday's Wear-Tyne derby against Sunderland, McClaren said he was happy for Mitrovic to continue his aggressive style.
"There is always a fine dividing line, always fine," McClaren said.
"He has played smart. I would say he has been playing smart, and that is what we have been telling him, be smart. That's what he has done.
"Smart and effective. You can play smart and be ineffective, but play on the line and play smart.
"He got sent off against Arsenal and could have been against Southampton, and they were not derbies, but that was a willingness to win and playing on the edge, on that line.
"He has shown a level of maturity in the last three games. But again, we are not getting carried away and saying, 'Woah!'.
McClaren added: "We knew there was a bit of the devil [in him], to be perfectly honest, and that has added to our game. We need that, but we need control and that is the key on Sunday."
