STONEHAM – Playing for the first time in 11 days, you couldn’t blame the Marblehead boys hockey team if it was a little rusty at the outset of its Division 3 North quarterfinal with Rockport on Sunday.The Headers quickly shook off the rust and unleashed a never-ending attack of shots at Rockport goalie Colby Foster, finishing the night with a 48-8 shots on goal advantage and cruising into a semifinal rematch against Shawsheen (Thursday at Chelmsford, 6:10) with a 7-0 win at Stoneham Arena.Last season, it was the Rams who stunned Marblehead in a shootout in the semifinals on their way to a North title and a state final berth.”We hadn’t played in 11 days and that showed a little bit in the first period,” Marblehead coach Bob Jackson said. “But I think we got better as the game went on and scored some pretty goals.”Senior defenseman Anders Gundersen was the ringleader of the Marblehead attack on Sunday. One of the most versatile players in recent memory on the North Shore, Gundersen scored a pair of highlight reel goals that saw him eat up nearly 300 feet of ice on end-to-end rushes before beating Foster with a pair of laser-like wrist shots. He added two assists as part of the win.”Anders has really started to get going the last couple of weeks,” Jackson said. “He’s a senior and knows his career is almost over and he’s taken it to another level.”Marblehead (18-2-3) might have been rusty in the first period but that didn’t stop the Headers from outshooting the Vikings by an almost unfathomable 19-0 margin in the opening 15 minutes.Foster, however, was more than up to the task as it took the first of Gundersen’s individual efforts to beat him. Picking the pocket of a Rockport forward at the Marblehead line, Gundersen wound his way through three defenders and then snapped a shot over Foster’s glove hand for a 1-0 lead after one period.The onslaught would continue in the second as Marblehead added nine shots before Rockport’s Zach Hill got his team’s first shot of the game against Tony Cuzner with 7:54 left in the second.It was still 1-0, however, late in the second when Gundersen’s second fantastic goal finally broke open the floodgates for the Headers.Taking a pass from Jake Kulevich in his own zone, Gundersen proceeded to skate around and through all five Rockport players before whistling a wrister over Foster’s shoulder with 5:54 left in the second.”In the past we’ve had 48 shots in a game and scored only once or twice,” Jackson said. “It was great to see us get some nice goals out there.”Three minutes later, Alex Whitmore cashed in on a scramble in front of the Rockport net to pick up his 10th goal of the year, assisted by Chris McLeod and Ryan Dempsey, to make it 3-0.McLeod closed out a 20-shot second period for the Headers with 8.1 ticks remaining when he snapped home a shot from the slot to make it 4-0 Marblehead.”We just kept telling the kids to keep working and be positive and the goals would come,” Jackson said. “And we picked our heads up and made some good things happen in the second period.”In the third, Marblehead kept coming as Austin Haley’s goal at 5:20 effectively ended the competitive phase of the game. Ben Koopman would add a power play goal at 8:27 before defenseman Jay King closed the scoring with his first goal of the season at 11:16.