Mido will prove a big success at Middlesbrough, says teammate Julio Arca.
"But even then, he has shown how good he is. He is going to get more pace and more confidence and then people will start to realise how good he is going to be for us."
Boro boss Gareth Southgate said: "They are different characters and different types of player. We loved having Mark, but that chapter has closed now in our book.
"Mido is the future and so are the other players we have brought in.
"He has already been a bit of a talisman for us, not only scoring the two in two, which is the perfect start for any striker, but his response in the dressing room, the way he has got the rest of the team fighting."