Martin O'Neill added a number of players to his squad in the summer transfer window and Cuellar, who left Aston Villa at the end of last season, believes that the Black Cats should be optimistic for the future.
The Spaniard said: "I believe we have a good blend of players in the squad – we have experienced players, we have young players, we have players who like to attack and players who like to defend."
Cuellar was also generous in his praise for defensive partner John O'Shea and insists that their experience is vital to the team.
"We feel confident, we have good communication with each other and I think we feel comfortable to play together," the 31-year-old added. "I think a lot of that is because we are experienced players and so we know what it needs for things to work."
Sunderland will host Liverpool at the Stadium of Light on Saturday afternoon.