The No. 1 Harvard men’s lightweight crew couldn’t have asked for a much better start to its spring season.

The Crimson swept all four races against Delaware on Saturday morning at Harvard’s home course on the Charles River. With the victory, the Crimson recorded its 20th straight win in the dual season. Both the 2010 and 2011 lightweight crews went undefeated in head-to-head racing.

The strong tailwinds that grew in intensity throughout the morning quickly became a factor in Saturday’s races.

“There was a wind that made the conditions tougher and tougher as the race went on,” said captain Tom Nesel, the six seat of the second varsity eight. I think all crews came out of the gates pretty fast and realized that it was going to be a fast race.”

The second varsity race was the closest of the morning, with the Crimson defeating the Blue Hens by a margin of 4.7 seconds. Harvard finished the course in 6:06.9.

The race seemed to be decided in favor of the Crimson until a mishap slowed down the boat’s pace.

“With about 250 meters to go, one of our oarsman caught a crab, which stopped the boat speed,” Nesel said. “We had to pick it back up.”

But the incident did not ultimately influence the outcome of the race.

“We had a pretty confident lead,” Nesel said. “We had that little setback with the crab, but after that we pulled back away again. We struggled quite a bit in the tougher conditions in the second half of the race, but we ended up pulling through.”

Nesel stressed the importance of maintaining mental toughness in the most difficult stretches of the race, especially in strong winds.  This allowed Harvard to hold on to its lead and come away from the race with a win.

“I was just trying to think clearly because there was a lot going on physically,” the captain said. “The more technical aspects of the stroke that you can think of during the hardest part of the race, the better you can perform.”

The first varsity eight’s race was much more one-sided. The Crimson finished in 5:49.9 en route to a 23.2-second victory over the Delaware crew.

“I thought it was a really good start to the season, especially because we were able to accomplish exactly what we set out to do with our race strategies,” senior coxswain Angela Chang said. “We just focused on our own race and doing the best that we could.”

The Harvard crew pulled away for an early open-water lead in the first 500-meter stretch of the race.

“One of our goals was to focus on our boat for the first 500, just moving well and being able to handle the cross-wind conditions,” Chang said. “We stayed calm and focused on the speed of our own boat early on.”

The Crimson freshmen also had a successful start to their first dual-racing season. The freshman eight finished its race in 6:03.6, defeating the Blue Hens by a margin of 12.6 seconds. The Harvard A entry of the freshman fours crossed the finish line in 6:55.2.

With Harvard’s first Ivy League matchups two weeks down the road, Delaware was an important preparatory race.

“It was definitely good to get a 2000-meter race in the legs,” Nesel said. “We hadn’t done it yet, and it is a very unique experience.  Getting warm in the legs for our Ivy opener in two weeks is important both mentally and physically.”

Chang also discussed the importance of Saturday’s win in boosting the team’s morale and motivation for improvement.

“I think it gave us confidence that what we are working really hard on every day is actually working,” Chang said. “We have two weeks until the Ivy opener, and we are just going to work on getting faster and faster every day.”

The Crimson lightweight crew will take on Cornell and Penn in Ithaca on April 7, when it will look to stretch its record of consecutive dual-season wins.

“We want to win every race we enter,” Nesel said. “We have had precedent in the past two years: Varsity has had undefeated regular seasons, and last year we had a Sprints Championship.  We want to keep that momentum going all the way to the National Championships in June this year.”

—Staff writer Alexa N. Gellman can be reached at agellman@college.harvard.edu.