The Ottawa Senators know they have something special in defenseman Erik Karlsson. So that’s why they wasted little time in making sure the blueliner will be with them for the rest of this decade.

The Senators Tuesday signed Karlsson, who’s just 22, to a seven-year deal worth $45.5 million — a $6.5 million cap hit, which is just a little less than Drew Doughty got from the Los Angeles Kings last season. The difference is, Doughty held out last year during training camp without a contract as a restricted free agent, while the Senators have taken care of Karlsson before he could become a RFA July 1.

Even though the Bruins got the better of Ottawa five out of six times last season, the recent games with the Northeast Division rivals have been highly competitive. Karlsson, a Norris Trophy finalist along with Bruins defenseman Zdeno Chara tonight in Las Vegas, has been a big part of Ottawa’s rapid overall turnaround and their battles with Boston.

Last season, Karlsson posted 3-3-6 totals in six games against the Bruins. He scored the game-winning goal in Ottawa’s lone win in the season series. He’s recorded just one assist in 11 games against the Bruins previous to the 2011-12 season.

Over the years Ottawa’s been entangled in several bitter contract disputes with players, and the Canadian capital hasn’t exactly been a highly popular destination of choice for free agents. That they were able to get a young budding star like Karlsson, who seemingly might even be better than he showed during his 78-point season, is a positive sign for those Bruins backers that savor a hotly contested race for the division title, and bad news for those hoping that Ottawa might become a pushover in the years ahead.