For all their pressure, Chelsea barely tested the opposition goalkeeper as they record two straight goalless draws for the first time since Roman Abramovich bought the club.
"You cannot be satisfied when you haven't won these games," said Benitez, whose two games in charge have been watched by the Russian.
"City are a top side, a team with a lot of options.
"Today, I saw a lot of positive things, sustaining the attacks and regaining the ball very high.
"I didn't like the two chances we gave away on the counter-attack, and when we didn't move the ball too quickly, but it's a question of time.
"We've only had a few training sessions. We need more time."