Two late goals in the space of two minutes gave the Toffees all three points but the centre-back has credited the Black Cats for their most improved overall performance.
Prior to the game Sunderland had only taken a total of 13 shots on target this season while Everton had hit 17 against Fulham the week before.
But Cuellar says he is happy that they produced some fine attacking football against David Moyes' side, leaving him optimistic about his side.
|A JOLLY TIME FOR THE BLACK CATS|
|4/1||Sunderland are 4/1 with bet365 to beat Fulham|
"We had good control of the ball and good spells in the game and really tested their goalkeeper. To lose after taking the lead is tough... but we have to take the positives from how we played.
"The players are down at the moment, because we played so well and lost, but we can take confidence from that performance, we know know we played well."