Defeat in the Jaws of Victory
The more Matt thought about it, the more satisfying he found Fisk's defeat. It wasn't just the triumph of law over villainy or the personal glee at finally knocking him down, or even the combination of both. It was the timing.
The Man in the Mask did his part and delivered the key witness, and then it was all nice and legal; the arrests of Fisk's lackeys and informants, the clearing out of the police station, the indictments of the Landman and Zack partners and the senator, even up to Fisk's arrest. Justice, plain and simple. The vengeance of the law catching up with the criminal.
Then there was the heart-stopping moment when Fisk got free. It would all have been for nothing if the Kingpin escaped. Defeat pulled from the jaws of victory. All the progress, might as well have never happened, because at least then Matt would have known who to watch. It was the bitterest feeling Matt could imagine.
The Devil hit the street, and then, just when Fisk thought he was in the clear, he was the one who snatched defeat from victory's jaws.