Last time Yale competed against ECAC hockey powerhouses Union and Rensselaer, the men’s hockey team defeated its toughest competitors yet to earn the first No. 1 national ranking in program history. They’ve topped the polls ever since.

This weekend the Bulldogs (17–2, 11–1 ECAC) will face off once more against No. 12/13 Union (16–7–3, 8–3–1) and No. 10 RPI (15–6–3, 7–5) in the hopes of extending their unprecedented nine-week run as America’s best college hockey team. But the Elis, who have struggled to generate offense in the opening periods of their past few games, have little room for error as they travel to take on two of the nation’s top five scoring defenses.

“These games are all about us,” forward Clinton Bourbonais ’14 said. “Coming into their barn, it would be nice to ice the crowd by scoring early and often.”

Icing the crowd will be especially important against RPI. The Engineers are hosting their yearly Big Red Freakout during the Yale game. The cacophony at the 1987 version of the school tradition — which annually packs the RPI rink — forced the NCAA to institute a rule forbidding the use of artificial noisemakers at games. Despite the ban, the Elis can expect a large, hostile crowd eager to see the nation’s top team go down.

That crowd might shake the Elis, whose only two losses this season have both come on the road. The Bulldogs dropped a game against the Air Force Academy in November and suffered a 3–2 loss at the hands of Brown two weeks ago.

Union and RPI are, at least by the rankings, better than either of those teams.

“We are going to have to play solid defense and take advantage of our scoring chances,” Bourbonais said. “We need to use our speed and hard work to wear down these hockey teams.”

The Dutchmen have used a shutdown defense and the nation’s best power play unit to stake out a spot in the middle of the top 25 all season. They rely not on any stars, but on six skaters who each have 20 points. That balance on offense makes Union particularly hard to contain when they are up a skater, and they enter the weekend’s games converting on almost 30 percent of their man advantages.

But Yale has contained that power play once before. In the two teams’ last meeting, Union failed to convert any of its six opportunities.

In that game, the Dutchmen’s stellar defense — which allows the second fewest goals per game in the nation — went to pieces as well. Union eased up on its typical physical game, repeatedly lost battles for loose pucks, and allowed the Elis to skate untouched in the offensive zone. Yale capitalized and demolished its opponents 5–0.

The Engineers, too, have one of the best defenses in the country, and allow a stingy 2.12 goals each game, a statistic that ranks just behind Yale’s mark. In fact, Union, Yale and RPI rank second, third and fourth in the country, respectively, in goals against average.

Both RPI and Yale have such stellar statistics in large part because of their last lines of defense. Goaltenders Allen York of RPI and Ryan Rondeau ’11 play in nearly every one of their teams’ games, and are both in the top ten nationally for goals against average and save percentage.

Senior forward Chase Polacek has been the key to the Engineers attack this season. Polacek has a team-high 34 points in 24 games, and ranks eighth nationally in points per game — just behind Yale star attacker Broc Little ’11.

Little’s output is tops among the Bulldogs, but both he and fellow Hobey Baker Award nominee Denny Kearney ’11 have entered dry spells of late. A Kearney empty-netter was the only goal either scored last weekend.

In Yale’s sweep of Clarkson and St. Lawrence last weekend, Kenny Agostino ’14 and Chris Cahill ’11 picked up the slack. The pair benefited from the passing of Andrew Miller ’13 — who leads the nation in assists — to combine for five goals.

Ultimately, the games will come down to a battle of work ethics, Agostino said.

“What makes these two teams good is that everybody has a decent amount of skill up front, but what separates a lot of teams is how hard they work,” said Agostino, who has seven goals in his past seven games. “We think we’re the hardest-working team in the country, and when you face hard-working teams, that’s what makes games exciting.”

The puck drops at Union at 7 p.m. Friday. The Elis compete against RPI at 7 p.m. the following day in Troy, NY.