The Spaniard has had a dire run at Monza this weekend, suffering brake, gearbox and engine problems in practice, and a broken roll-bar in the crucial 'Q3' qualifying segment.
"It is a shame because it would have been the easiest pole," Alonso, who is instead just tenth, is quoted by Marca newspaper.
"I will try not to lose many points to (Sebastian) Vettel," he said, referring to his nearest championship rival.
"Actually we should be increasing the lead in the championship. These are errors we said we needed to avoid."
But in June, Alonso came from eleventh on the Valencia grid to win.
Can he do it again, this time on Ferrari's hallowed ground?
"We know that (Valencia) was an unique opportunity and we can't tell everyone that we can do that (again), because then if we have a normal race and finish eighth and ninth, everyone thinks we did a bad race," he said.