When a clear opening eventually came their way late in the second half, substitute Olivier Giroud, who netted 21 goals for Montpellier last season, fired wide.
"We played with a good spirit, were serious and we put the effort in, but we lack sharpness and fluency at the moment to be dangerous in the final third," said Wenger.
"The few chances we had, we could not convert them.
"Sunderland defended very well for the whole game, and we lacked something - sharpness, also quality and accuracy in the final pass."
Wenger added: "The formula didn't work with three strikers up front and we were not well balanced, we did not create enough because they blocked our midfield."