For the past couple of days, Guy Boucher steadfastly would not allow himself the luxury of looking ahead, wondering what it would feel like carting a 3-1 series lead against the Boston Bruins back home.Bad karma and all that, reasoned the ultracautious Ottawa Senators coach.Boucher no longer has to wonder as his Senators delivered their best overall performance of the postseason so far to earn a tight-checking 1-0 victory at TD Garden on Wednesday night to bring the Bruins to the brink of extinction from the Stanley Cup playoffs. “When I was in junior I had Johnny Bower for a day and that was the story.“The first time he ever came out, sliding at the guy and he was nervous and I was nervous. It doesn’t matter who you play, everybody has a chance against anybody.”A lot of the Senators’ success through the first three games can be traced to their ability to cap the offensive exploits of Patrice Bergeron and Brad Marchand, two of Boston’s top snipers over the course of the regular season.In the first three games of the playoffs, however, their contribution has amounted to one goal apiece, a factor that Boucher credits to what he described as Ottawa’s “pack mentality” on defence.“We haven’t really done anything different against them that we would do against Crosby or Ovechkin, McDavid and those guys,” he said. The poise, especially under pressure – he [Karlsson] was skating backwards with guys coming at him.“It was an all-world play.”Craig Anderson earned the shutout in the Ottawa net where he was not tested all that often but came up big when called on.With the win, the Senators have taken a 3-1 stranglehold over Boston in the best-of-seven NHL Eastern Conference quarter-final.The series now heads back to Ottawa where the Senators can wrap it up with a win in Game 5 on Friday night.In the history of the Stanley Cup playoffs, teams that have gone up 3-1 have gone on to win the playoff about 90 per cent of the time.For two periods the two teams traded punches, but with no knockout blows. “Home ice doesn’t mean a thing. “We just developed some pride in our defensive games, trying to allow the least shots possible whoever we’ve played against.”The Senators expected the Bruins to come into Wednesday’s game a desperate warrior – and they were, carrying much of the play to Ottawa over the first half of the first period.Marchand had Boston’s best opportunity, breaking in all alone on Ottawa goaltender Craig Anderson, who stonewalled the Bruins’ skater on the deke.Marchand was dangerous throughout the goalless opening frame, once sneaking in behind the Ottawa defence late with Anderson jumping out and laying himself out flat to make the save.Anderson was asked where that move came from?“Johnny Bower,” he said, providing the name of one of the game’s all-time great goaltenders. Stanley Cup Playoffs: The latest news and resultsAnd it was Bobby Ryan who continued his postseason renaissance for the Senators, potting the winner at the 5-minute, 49-second mark of the third period that would ultimately crush the spirit of the Bruins.After Erik Karlsson sent a slap-pass toward the Boston net, Ryan had two whacks at the puck stationed just outside the crease before he was able to shovel it in behind Bruins goaltender Tuukka Rask for the game’s first and only goal.For Ryan, who toiled through a dreadful, injury plagued regular season, it was his third goal of the postseason. “I waited just long enough to see it come in. The play for the most part was cautious and good scoring chances were at a premium as the game remained goalless heading into the third.The series as a whole has been tightly contested, with two of the first three games requiring overtime to determine a winner, including the Senators’ 4-3 win here on Monday.That was one of four NHL playoff games that day that required extra time.“It’s harder to get to bed, I can tell you that,” said Ottawa coach Boucher, adding there’s really no such thing any more in the modern NHL as a prohibitive playoff favourite.“Whether you finish first, second, third or whatever I’ve been saying it all year – just get in those playoffs,” Boucher said. I’m just glad it worked out.”Karlsson had Ottawa’s best chance, jumping up into the rush and finding himself face to face with Rask, the Boston goalie, who had to make a solid save on a tough chance.It marked the third time in four games of the series in which there has not been a first-period goal.The Bruins thought they’d finally broke through at the 10:30 mark of the second period when a shot from the blueline by Charlie McAvoy beat Anderson. The shot might have been tipped in front.Regardless, Ottawa challenged the play, noting that Noel Acciari was offside and, after a video review, the officials agreed and it was judged a non-goal, sending the partisan Bruins fans into a ranting fury.Anderson made 22 saves for the shutout. And for Karlsson, the superb Ottawa defenceman, he has now assisted on five of the 10 postseason goals the Senators have tallied in the series, series and his most recent helper was a thing of beauty.It was sort of a fake shot that manoeuvered Rask just enough out of position to provide the opening for Ryan to slip the puck home.“Yeah, I almost gave up on it too and just kind of went to the net,” Ryan said.