The Teessiders have re-ignited their Sky Bet Championship campaign with successive victories over Millwall, Burnley and Reading, and head for Bolton on New Year's Day with the Spaniard delighted at the options he has at his disposal.
He told the club's official website: "When I arrived here, the team had 14 or 16 players; now I have 26 players who can play in every game, and that's important.
"Every player can go to the training ground feeling he can play in the next game.
"It's difficult to know everybody when you arrive, but after just one week I saw how capable they were and the most important thing for me is the attitude of my players. I trusted in my squad at the beginning."