I know you didn't say anything explicitly about psychological factors, but why else would it be hard to beat a team three times in one season? And to be clear, I mean why would it ever be harder to beat a team a third time if you've already beaten them twice rather than one or zero times in the regular season? It has to be something psychological because certainly there's typically not a physical or strategic reason, and definitely not in this case since the games were in November.
I hear that "tough to beat an opponent three times" line most often from NFL analysts when divisional opponents rematch in the playoffs, where there's more likely to be a strategic element -- maybe you emptied your playbook already and your opponent has made adjustments.
When you've had success in the regular season, psychological factors can cut both ways. They can give the winning team more confidence and the losing team hopelessness, or they could give the winning team too much confidence and the feeling they have nothing left to prove while the losing team feels they're better than they've shown. Our resident Dartmouth poster is suggesting that the Green has "unfinished business" in Cambridge, but I have to believe those two November losses bite at the poster more than the players, who haven't invested in a Harvard-Dartmouth rivalry for nearly as many years.
What's the right psychological approach for a team to take in the playoffs when you've had some success against an opponent in the regular season? You hear coaches say all the time "our records are all 0-0 now." While certainly that's technically true, I think you want to strike the right balance, and players probably won't completely forgot the past success anyway. I think you'd want to go into the game knowing that you have a lot left to prove, but also maintain some confidence that you match up well with the opponent and you'll be rewarded for executing your game plan.
Quinnipiac reminds me of BC in having one superstar forward and one all-League goalie. I feel they underachieved this year and have a lot to prove. I have this sense they'll win the ECAC semifinal and lose in the final no matter who they're playing. That's kind of been their pattern all season.