Big hits, big kills, a big defensive play and a big goal.

The Senators rose to the occasion and had one of their best opening 20 minutes of the season against the St. Louis Blues Monday. Had they played even half of their previous first periods the same way, they’d have 5-7 more wins.

Zack Smith set the tone physically and with a couple of penalties, and surviving his back-to-back minors helped swing momentum to the home side early. Robin Lehner’s stops off Kevin Shattenkirk and Brenden Morrow were instrumental in the kills. He also had some luck on his side, as the one shot that slipped behind him hit the post and rolled across crease.

Erik Karlsson was outstanding in the opening 20, making two solid D-zone plays and sneaking in behind the Blues blue liners to force one of two great saves by Brian Elliott (the other off Kyle Turris) before Jean-Gabriel Pageau converted a Bobby Ryan setup for the only goal of the frame.

Pageau also drew a roar from the crowd when he drilled Jay Bouwmeester into the boards on a penalty kill.

The Senators, who have been mostly horrible starting games this season, need to remember what they did in the first period Monday.

If they can somehow make a habit of it, this season is not lost yet.