He said: "Afonso is more settled in the area now and by the end of last season, you could see just how much he had adjusted to the type of football over here.
"He will definitely score plenty of goals for us next season. He is such a natural finisher - give him half a chance, and he puts it away.
"Tuncay has had a full season to get used to the Premier League and I think he will score loads of goals too.
"Having a good tournament for Turkey in the European Championship will boost his confidence even more.
"I think Boro fans will see what a fantastic player he really is next season.
"If those two can stay injury-free, I am certain they will have a massive impact for us."