Against Princeton, Harvard played well in the second half, but conditioning was a factor.
"Fatigue was a problem on Saturday," Burg said. "It was a hot day and there was a lot of running up and down the field throughout the game."
The Tigers' goaltending was stronger in the final 30 minutes as well, and Princeton capitalized on more of its opportunities with quick goals off faceoffs.
"In the first half, we played like we should," Burg said. "I think the problem in the second half is mental. It's hard to maintain focus for the whole game, and are goal must be to play for a full 60 minutes."
Facing B.U., Yale, and Princeton, Harvard played step-for-step through the first half with three of the Top 10 teams in the country, an incredible accomplishment for an unranked team.
Nevertheless, the Crimson must find a way to play that way in the second half as well if they hope to upset No. 9 Dartmouth this Wednesday.
"We are optimistic about the game with Dartmouth," Burg said. "We've seen what we can do and we've had glimpses of greatness."