Whenever I come across a comment about Zabuza's strength it's that he's a weak Jounin if not weak that he's a lot weaker than Kakashi. Well I personally believe both to be untrue. I'd actually go as far as to put him about on the same level as him or just a bit weaker. If not for the help that Kakashi received from the rest of the team, Kakashi would've been killed by Zabuza. In the first few moves of the fight, was basically trade offs and such. Kakashi immediately activates his sharingan upon Zabuza's arrival saying that he cannot beat him without it. Then they begin their fight. Both of them seemed equally matched in speed but Zabuza overcame Kakashi more than twice and Kakashi only hit Zabuza' mizu bunshin clone once. Then Kakashi mizu bunshins behind Zabuza and leads to this. As you see, Zabuza was able to easily outmaneuver Kakashi and could've killed him right then and there if not for the fact that he went off to finish Naruto, Sasuke, Sakura, and Tazuna. If you do not believe so then then enext image. Kakashi even admitted defeat. Not once in the first battle did Kakashi overcome Zabuza aside from the mizu bunshin trade off after Zabuza was able to pass Kakashi without his notice. Then afterwards Zabuza was able to handle Kakashi who had no inihibitions and trap him in the prison. Zabuza Could've finished Kakashi right there defeating "Copy Ninja Kakashi" who did not hold back once during the fight. Not until after he wasted many mizu bunshins on the rest of team 7 was Kakashi able to finally get out with team 7's help. They had subsequent trade offs and they were easily matched in speed and strength(this is after Zabuza used jutsus therefore wasting chakra on "outside interference" before he was able to handle Kakashi). Not until Kakashi used his intelligence and and phscologically beat Zabuza was he able to finally pull off a jutsu to defeat him. Though that trick as figured out by Zabuza later on so it wouldn't work twice. The 2nd match, Zabuza simply put up the mist and was playing around with Kakashi till he was caught off gaurd by Kakashi's dog summonig and chidori, he was once again outsmarted due to his overconfidence and in a trick that will not work on Zabuza again. But all these could've been avoided and Kakashi dead if he had wanted to finish him off in the first fight. Despite the fact that Kishimoto obviously displayed their abilites as matched (Zabuza superior in the first scuffle, Kakashi in the last), people seem to assume Zabuza was "pwned" when Zabuza was the one doing the owning (look at the images above) first. I do believe that Zabuza is greatly underrated. And that he isn't far below in skills of Kakashi. Though in terms of strategy he does pale a lot in comparism to Kakashi but not in others skills.