The Black Cats came from a goal down to win 2-1 at Stamford Bridge.
Afterwards, Maresca said: "I think in general we were not good enough. When you are not good enough in the Premier League, we know that the consequence can be the bad one. The second goal we conceded, I said already many times, when you are not able to win, it's important that you don't lose.
"But even with that, it's not a transition because a transition when you are open or it's 1v1, it's just one long ball in behind. We are 2v1 with the two central defenders and we didn't defend properly.
"The first goal came from a throw. Again, it's difficult to deal because they bring six, seven, eight players inside the box, so it's difficult. But overall, I think we were not good enough.
"They told me this morning that before today's game, we had exactly the same points as last year, after eight games. Dropping points today, I think we are still in October. We need to improve many things and see where we are in March, April, May and then decide."
He also said: "Lack of creativity. We didn't create a lot, apart from the goal probably. And we struggled. Also, I think, you know, we need to perform. We need our players to perform 100%. And even with 1-0, we lost some duels, we lost some second balls. And against this team, you need to win that."