Turnovers and mental mistakes ultimately proved to be the downfall of the Boston University men’s basketball team in Saturday’s 79-68 overtime loss to crosstown rival Harvard University at Case Gym.

From the opening tip, both the Crimson (9-1) and the Terriers (6-3) brought high-pressure defense. Harvard’s defensive intensity, particularly from guard Wesley Saunders and forward Kyle Casey, forced early turnovers from sophomore guard Maurice Watson Jr., senior forward Dom Morris and senior guard D.J. Irving in the game’s opening minutes. This allowed the Crimson to open up a 10-5 lead with in the first five-and-a-half minutes of the opening half.

The Terriers played catch-up from there, countering every Crimson run to keep the deficit manageable. Pressure from the Crimson defense, coupled with the need to get back into the game, resulted in the breakdown of BU’s offensive rhythm and poor shot selection.

“I think defensively, [Harvard] got up and pressured us,” said BU coach Joe Jones. “They took away some passes, and any time a team does that to you, it kind of takes you out of rhythm. They were taking away some passes and kind of forcing us to play more one-on-one at times. I think at times in the game, that took us out of rhythm and led to some mistakes.”

With a strong defense, Harvard went into halftime nursing a 32-30 lead. The Terriers were held to shoot just 38.7 percent from the field in the half, but were fortunate to hold the Harvard offense to just 40 percent, keeping the score close.

In the second half, the Terriers came out invigorated, taking better shots and making smarter decisions on the ball. Two free throw makes from freshman guard Cedric Hankerson tied the game at 48 with 10:56remaining. Harvard would then go on a quick scoring run to hold a 10-point lead with 6:40 left in the game.

As the end of regulation neared, the Terriers pulled everything together, going on a 16-6 run to force the game to overtime, thanks in part to BU shooting an improved 48 percent from the field for the half. John Papale, who had not made a basket in the first 39 minutes of play, hit two clutch 3-pointers in the final minute of regulation to aid the comeback.

Although the Terriers had all of the momentum going into the extra period and the noise of the crowd on their side, BU could not get out of its own way to start overtime.

Three turnovers in consecutive possessions in overtime allowed the Crimson to pull away for good. The Terriers shot just 14 percent in the period, only making one basket. Watson missed two key free-throw attempts that would have cut Harvard’s lead to two points with 2:42 remaining. Instead, the Harvard lead swelled and the game ended in a 79-68 Crimson victory.

“I felt like after John [Papale] hit the first shot in overtime, [Harvard] turned up their defense and we played a little timid,” Morris said. “We ended up turning the ball over, then fouling, then turning the ball over and fouling again. We didn’t play with confidence. I felt like we were the better team. They just got the best of us today.”

While the Terriers out-rebounded the Crimson 23-18 and continually pressured the Crimson, in the end, Harvard’s plus-5 turnover ratio proved to be the deciding factor in the game. Morris ended the night with five turnovers, while Watson committed four. The Terriers also went just 12 for 20 from the charity stripe.

“We average probably around 10 or 11 turnovers a game and we had 15 tonight,” Jones said. “You can’t turn the ball over against this team, they’re too good. We’re even on the glass, we turn it over and then we don’t make open shots. That’s the game right there.

“You can say whatever you want about all the other things that happened, but we can’t have 15 turnovers. If we get 10, then I think we have a good shot.“