What a difference a week can make.

Seven days ago, the Harvard varsity lightweights opened their season with a dominant performance in Ithaca, where the first varsity dismantled crews from Penn and Cornell in a one-sided fashion uncommon to lightweight rowing.

But on Saturday, in the only home race the lightweights will have all year, the Crimson fell flat in front of its partisan crowd.

Harvard’s first varsity dropped a back-and-forth battle to Dartmouth on Saturday, relinquishing the Biglin Bowl for the first time in three years. Though the second varsity rowed to a four-seat victory, extending its undefeated dual streak to 13 wins over 26 opponents, the Big Green took home the Biglin Bowl in an upset bid.

“Maybe we were a little complacent after this past weekend,” said senior varsity bowman Alex Phillips. “One of the things we were saying afterwards is that this is a good test and it gets us refocused.”

Both varsity races stayed close throughout, but it was the frustrating to-and-fro of the first varsity race that did in the Crimson. A sluggish start put Harvard six seats down as both boats settled to a race pace for the first 500 meters, but the Crimson kept Dartmouth from adding any more to its lead in the opening half of the race.

A midway push helped the Crimson gain four seats back, trimming the Dartmouth advantage to a mere two seats.

Then the Big Green killed Harvard’s move, cranked the stroke rating, and responded with another move to gain back the four seats it had lost at the 1,000 meter mark.

“We made a move and then just sat there—it’s extremely frustrating,” senior two-seat Wes Kauble said. “You’d like to be able to get through a boat, and to get within two seats and give it back ten strokes later is not what a crew wants to do.”

Throughout the second 1,000 meters, the Crimson continued its game of catch-up, using an increased stroke rating in concerted pieces to try to pull even. Twice more Harvard pulled to within two seats, and twice more Dartmouth quelled the move and responded with one of its own to pad the margins again. Never did the Crimson pull even, and never did the margin grow to more than six seats.

The separation stayed consistent through the finish line, when the Big Green crossed in 6:16.0 and Harvard followed suit in 6:18.3, exactly six seats behind.

The second varsity race proved just as dramatic, although the first 1,000 meters played out in line with the routs of last weekend’s competition on the road. The Crimson took a quick three-seat lead off of the start and built the margin to a length as both boats went under the Mass. Ave. Bridge at the midway point.

But Harvard never was able to establish open water, and Dartmouth took advantage of the contact with the Crimson’s boat to make a move at the 1,000.

“We were in a position in that we were doing well, but it was kind of bad, too, because anything within a length is anybody’s game,” senior stroke Chip Schellhorn said.

The Big Green walked up five seats on Harvard in the third 500 meters, setting up a final 500 in which the Crimson held just a three-seat lead.

“I think their rating was higher than ours was—that was part of it,” Schellhorn said. “We were just a little complacent after the first 1,000, and we had just started sitting on them.”

Dartmouth’s higher rating helped pull the Big Green close in the third 500, but Harvard never let the lead shrink beyond three seats. The Crimson’s sprint led to a separation of five seats when the Crimson crossed in 6:28.5 and the Big Green followed in 6:30.3.

“I’ve got complete confidence in our ability to row even if we’re getting outstroked,” Schellhorn said. “We’re good at executing our race plan down to a ‘t’. We just kept our composure and stuck it out to the very end.”

Dartmouth did claim victories in both freshman races to take the Biglin Bowl from its usual perch in Newell Boathouse. Harvard has the chance to defend another cup win next weekend, as the lightweights travel to Annapolis with their heavyweight counterparts to take on Navy in the annual Haines Cup races.

“If you’re not pushing yourself to go faster every week, you can be damn sure that other crews are pushing to get faster and they will catch up to you,” Phillips said.

And on Saturday, they did. But as this weekend showed, anything can happen in a week.

—Staff writer Aidan E. Tait can be reached at atait@fas.harvard.edu.