When I sat down to watch Game 6 of the Boston-Philadelphia series in the NBA’s Eastern Conference semi-finals, if you’d have told me that Paul Pierce and Kevin Garnett would each have 20-plus points and 10-plus rebounds, I’d have figured the Celts were in good shape, and could fit enough offense around them. If you told me that Boston would win the rebounding battle 48-37, I’d have figured the series was all but over. Both of those things happened, but the 76ers clamped down on the defensive end, the Celtics shot a miserable 33 percent from the floor and Philly got a survival win, 83-75 and set up a decisive seventh game on Saturday.