Why a win instead of a save?

Not that I really care, aside from just curiosity, but I'm kind of baffled as to why Aroldis Chapman was given a win instead of a save in this game. He came in to pitch the 9th with his team up 12-9. Any thoughts?

http://onlinegames.strat-o-matic.com/game/267598/801

The starting Pitcher failed to go 5 but left with the lead he isn't eligible for the win you never lost the lead therefore the scorer is allowed to pick the pitcher who pitched the best to receive the Win both other pitchers got hit for runs so he choose the only guy with a clean slate

rudy

What rudy said is the way the rule is written and this game has a good example. In real life you may see one game per year where this happens. Almost always the guy who pitched the 5th inning, Affeldt in your game, would get the win. Easy way out for official scorers who don't want to make the home team mad or else they lose their cushy job.