Most crews do not have the luxury of classifying a two-length victory as a close race, but the Harvard men’s heavyweight first varsity has been that dominant this season.

The U.S. Naval Academy gave the Crimson its closest race of the season in Annapolis on Saturday, but that hardly meant the outcome was in doubt down the stretch. Harvard defeated Navy by 5.7 seconds and Penn by 13.8 seconds to win the Adams Cup for the fourth straight year and finish April undefeated for the second straight season.

The race was Harvard’s last before Eastern Sprints, the 15-boat regatta that is typically the Crimson’s most competitive of the spring. Despite its perfect record so far, Harvard is no heavy favorite, especially given that its first varsity pulled off the same undefeated feat last year only to be humbled by Wisconsin at Sprints, where the Crimson has not won the top race since 1990.

One difference between this spring and last, however, is the margins by which Harvard has been winning. The gap between the Crimson and the Quakers on Saturday was the largest since 1981, far from the first victory of historic proportions for Harvard this spring. The most recent USRowing poll recognized the Crimson by pushing it past Wisconsin to the nation’s No. 2 ranking, behind only defending national champion California.

Harvard was able to beat No. 5 Navy and No. 11 Penn convincingly even though Saturday’s effort fell short of the boat’s best race this season.

“It was really early in the morning so we were a bit stale, but we executed the race very well and got a victory, which is all that really matters in the end,” said junior stroke Kip McDaniel.

The start was not as strong as in recent weeks, according to McDaniel, but Harvard still held the lead by a few seats after the first 20 strokes. McDaniel said Harvard had its best 20 strokes at the 600-meter mark after passing a bridge—the Severn River course’s only major landmark.

McDaniel praised his boat again for staying aggressive down the stretch, which will be crucial when Harvard faces tougher competition in two weeks at Sprints from defending champion Wisconsin as well as opponents who have improved this spring.

Harvard’s second varsity won its race by just 1.3 seconds over Navy to stay undefeated for the season as well. The Crimson won despite losing juniors Tyler Winklevoss and Jonathan Lehe to injury this weekend, as senior Curran Hendry and sophomore Nick Hodler filled in admirably for Harvard.

Junior Will Riffelmacher said Navy led the second varsity race until about the 900-meter mark. The Crimson made its move at the halfway point and maintained a half-length lead for the last quarter of the race.

“I think it was one of our best races of the season because we had to be very stubborn for the entire race,” Riffelmacher said. “It was good because we proved to ourselves that we could row from behind and win.”

The Harvard third varsity and both freshman boats also posted victories on Saturday. The first freshman boat upped its record to 5-1, with its only blemish coming against Princeton last weekend.

—Staff writer Jessica T. Lee contributed to reporting of this article.

—Staff writer David R. De Remer can be reached at remer@fas.harvard.edu.