That marks a disappointing return for the Azzurri, who last year claimed the impressive scalps of both France and Ireland and ended up fourth in the table.
This time around they pushed Wales hard in their opener, came within a whisker of beating Scotland but were put to the sword in the last two weeks by both Ireland and England.
And with a World Cup in 18 months time, Brunel admits it is a case of back to the drawing board for him and his players.
"We've gone a step back in terms of our ambitions but also our capabilities," he said.
"Today I saw the team were in difficulty in physical terms after 20 to 25 minutes. We have to seriously ask ourselves what our ambitions are and how we want to go about achieving them."