WARRENDALE — Serra Catholic had a window of opportunity. Mars goalie Christian Knapp slammed it shut. Once the Planets weathered the storm, the rout was on. Mars killed off three second-period penalties before scoring two goals in a 49-second span to seize complete control of an 8-2 victory over the Eagles in the Penguins Cup Class A hockey quarterfinals on Wednesday night at Blade Runners Ice Complex. Trailing 2-0 in the second, Serra Catholic enjoyed a 5-on-3 advantage for a 1:47 stretch and had another power-play chance later in the frame. “We had a rough second period,” said Mars coach Steve Meyers. “They got us in penalty trouble; we kind of fell into some of their traps.” Knapp and the rest of the Planets never wavered. Serra Catholic (12-12) fired quality shots at the net, but Knapp continually turned the Eagles away. “I was definitely in the zone,” said Knapp. “Once you get a couple of shots on the power play, you start to get in the groove and I really believe that during that 5-on-3, that’s when I hit my stride.” Knapp made 14 of his 27 stops in the second period. “Christian stood on his head,” said Meyers. “He played great.” As the second penalty kill came to a close, Ian Houk-Graves sent the puck fluttering from blue line to blue line and connected with Nick Berteotti, who cashed in on the breakaway for his second of three goals in the game. Just 49 seconds later, Nick Makozy made it 4-0 off an assist from Reed Salada. “Getting the two there at the end of the second period was huge,” said Meyers. “You get a little momentum swing when you get that big kill and then to score that goal right after, it lifted us.” The Planets (18-3-1) initially struck when Kyle Thomas stuffed home a rebound off a blast from Michael McCann with 4:12 remaining in the first period. Berteotti extended the lead to 2-0 with 13:52 left in the second frame on a well-placed pass in front of the net from Ed Schwadron. “Our goal was to come out and jump on them early,” noted Meyers. Frustration seemed to boil over for the Eagles, who committed 10 penalties in the final 7:06 of the game. Mars took advantage, as Craig Mazzotta, Berteotti and Trevor Tisdale all tacked on goals with a man advantage.