The Brazil international swapped the Camp Nou in the summer for Paris Saint-Germain in a record-breaking €222m (£200m) move, and there were concerns as to how Ernesto Valverde's side would react following such a loss.
Barcelona as a whole have looked a more reunited outfit compared to the previous 12 months, Supercopa de Espana defeat aside, and Messi believes Neymar's absence has been a significant factor in that.
"Without Neymar we are more balanced", the Argentine explained in an interview with World Soccer, as quoted by Marca.
"His departure meant a change in our way of playing, we lost a lot of attacking potential, but it helped in the defensive sense.
"We are currently very well armed in the midfield; this makes us stronger in defence."
Los Cules take on defending Premier Leaguetitle holders Chelsea in their upcoming Champions League
last-16 clash next month, a side Messi has failed to score against in his eight attempts, but the 30-year-old believes it is in fact this year's English champions elect who pose the greatest threat in the competition.
"Manchester City are one of the strongest teams in the world at this moment", he added.
"The same goes for PSG, but there is a lot of football left and I don't rule Real Madrid out.
"They have a lot of quality and experience, then there is Bayern Munich who are a great team who will fight to the end.