When you play a team twice in a season, it gives you a chance to figure out what the other team is doing. The team that wins the first game is not normally going to make huge adjustments to what they did in the first game. Why would they? They won! The team that lost the first game has more they can and must adjust simply because they lost the earlier game. If the two teams are in the same ball park as far as talent level is concerned, it does give something of an advantage to the team that lost the first time. That certainly doesn't guarantee the team that lost the first time is going to win the second game. There are a whole lot of other factors at play, but it is one reason a second game often plays out quite a bit differently from the first.