The Italy star believes the Paris Saint-Germain defender allowed him too much space for his piledriver finish in the Confederations Cup clash on Saturday
Giaccherini netted a thumping drive shortly after the start of the second half to level the score at 1-1, although his goal could not stop his side slumping to a 4-2 defeat.
"Mario [Balotelli] gave me a great pass and then I saw Alino [Alessandro Diamanti], but as Thiago Silva did not come towards me, I tried to run into the space and scored a fine goal," the 28-year-old told Rai Sport.
"I was quite far out on the right, so perhaps Thiago Silva underestimated me, as he thought I couldn't possibly score from there."
The Juventus star also spoke about his delight at having found his place in the national side under coach Cesare Prandelli as he looks to secure a spot at the World Cup next year.
"I feel as important as all my team-mates, because we all feel the coach has faith in us," said the Juventus man.
"Everything I dreamed of is coming true and now that I am here I'm trying to give my all.
"Of course I'm thinking about the World Cup, but also keeping my feet on the ground, as anything could happen in the next year."