The Spur's defense wasn't really the problem (although there were too many second chances). The Spurs had an extremely difficult time getting their offense going, with their key players having more off nights than on - I mean, no disrespect to Barry, but when he's your number one performer out of Parker, Duncan and Ginobli, you've got a serious problem offensively.
And to reiterate my point, it's not about who you have on Kobe; you can't shut him down (although Bowen did better at that job than a lot of players have). It's about shutting everyone else down and trying to make Kobe the only scorer; I doubt Kobe can win 4 games all by himself. Assuming the Celtics have kicked this "we can't win a game on the road" BS, they have a much better chance against the Lakers than the Spurs did.