After successive defeats by Fulham and Huddersfield, the Magpies belatedly opened their account with a 4-1 victory over Reading at St James' Park, although Benitez later admitted his team remains a work in progress.
Asked how much better it can get, the Spaniard said: "Much better. How much is difficult to quantify, but I'm sure that we will improve. There will be some bad games, for sure, but we will improve.
"I didn't want to say the other day after losing two games there were 44 games to play, now 43, but it's the reality. The reality is you don't have too much time to prepare the team during the week, so you have to do things at the same time that you are trying to win games, and that's more difficult.
"But it's like this and hopefully these three points will give us a little bit of confidence for the next games."
Midfielder Isaac Hayden fired the home side into a 20th-minute lead, but for the third successive game, they conceded on the stroke of half-time when Garath McCleary converted a penalty awarded after debutant Ciaran Clark's challenge on John Swift.
However, Matt Ritchie restored Newcastle's advantage from the penalty spot early in the second half and Dwight Gayle's double wrapped up the win.
Benitez said: "It was important for me, for the fans, for the players, for everyone here to get three points today. The first two games without playing so badly, we didn't get any points.
"Today we showed character, a good reaction after the goal we conceded, and that's what we have we to do, play well sometimes and show character all the time."