DURHAM, N.C. -- Sophomore attackman Josh Dionne scored three goals while senior goalkeeper Mike Rock posted 12 saves as 15th-ranked Duke defeated visiting Harvard 11-8 on Monday night at Koskinen Stadium.

"I think we were very happy with our effort for three quarters, but we were very unhappy with our fourth quarter," head coach John Danowski said. "We committed four fouls. We turned the ball over 10 times. Fortunately we had a comfortable enough lead, but that's a formula for disaster somewhere down the road. While we're delighted to get the win, we have to be extremely mindful that we need to learn from tonight and three quarters is not good enough in general."

After battling to a 4-4 deadlock at intermission, the Blue Devils broke the game open by scoring seven unanswered goals in the third period. The run started with three goals -- including two by Jordan Wolf -- in the first four minutes of the quarter. A tally by Robert Rotanz with just 12 seconds left in the period pushed Duke's lead to 11-4. Duke held the Crimson without a score over the span of 18 minutes in that 7-0 stretch.

Harvard (2-3) netted four goals in the final period to account for the final margin.

"We just have to play for four quarters," Rock said. "We have a big game this Friday against UNC and if we want to win that game we have to play for 60 minutes. We can't just play for three quarters like we did [Monday]."

The Crimson jumped on top 2-0 with goals from Daniel Eipp and Will Walker before Dionne got Duke on the board with a goal from Christian Walsh late in the opening quarter.  Dionne would eventually give the Blue Devils a 4-3 lead, but it was short-lived as Jeff Cohen's marker with 44 seconds left in the half knotted the game.

Walsh and Wolf each carded two goals and two assists on the night while Rotanz finished with one goal and one helper.  The hat trick marked the third of the season for Dionne, who increased his ACC-leading goal tally to 14 on the season.  Harvard was led by Cohen, who scored five goals, and Eipp's one-goal, two-assist evening.

In making his first start in the Duke net this season, Rock registered a career-high equaling 12 stops, including nine after halftime.  Michael Manley spearheaded Duke's defensive effort with two caused turnovers and three ground balls while adding an assist in transition.  Brendan Fowler won five-of-seven faceoffs for the Blue Devils.

In the Crimson cage, Jake Gambitsky was credited for 11 saves.

The Blue Devils won the ground ball battle 32-20 and were 2-of-4 on man-up opportunities. Harvard also finished with two extra-man goals.