Batherson also had an assist,
Derick Brassard
and
Scott Sabourin
scored, and
Magnus Hellberg
made 18 saves for Ottawa, which finished the preseason 5-3-0.
Cole Caufield and Kaiden Guhle scored, and Jake Allen made 26 saves for Montreal, which did not win a preseason game (0-6-2).
Caufield opened the scoring with a power-play goal from the left face-off circle to give the Canadiens a 1-0 lead at 8:47 of the first period.
Brassard, on a professional tryout contract with the Senators, tied it 1-1 at 3:48 of the second period by poking in a rebound for his first goal in four preseason games.
Brassard had an assist on Batherson's game-winner.
Sabourin scored at 15:17 to put Ottawa ahead 2-1, beating Allen after initially losing his balance.
Guhle tied it 2-2 at 18:40.
Blues 6, Blackhawks 0:Jordan Binnington made 24 saves for the St. Louis Blues in a 6-0 win against the Chicago Blackhawks at Enterprise Center in St. Louis.
Ivan Barbashev scored twice, and Jordan Kyrou had a goal and an assist for the Blues, who finished the preseason 6-2-0. Brayden Schenn, Robert Bortuzzo and Jake Neighbours each had two assists.
Petr Mrazek allowed six goals on 25 shots for the Blackhawks in their preseason finale (1-5-0).
The Blues scored three goals in 2:10 during the first period. Barbashev made it 1-0 at 9:48, deflecting a slap shot from Bortuzzo. Nikita Alexandrov scored 23 seconds later for a 2-0 lead at 10:11, tipping a shot from Bortuzzo.
Kyrou pushed it to 3-0 at 11:58 after a pass from Schenn.
Robert Thomas scored a power-play goal 2:59 into the second period for a 4-0 lead.
Ryan O'Reilly made it 5-0 at 10:19, and Barbashev scored again at 17:05 for the 6-0 final.
Binnington made nine saves in the third period.
Lightning 5, Panthers 2: Vladislav Namestnikov scored a natural hat trick and had an assist for the Tampa Bay Lightning in a 5-2 win against the Florida Panthers at Amalie Arena in Tampa.
Namestnikov, who signed a one-year, $2.5 million contract with Tampa Bay on July 13, finished the preseason with six points (five goals, one assist).
Nikita Kucherov and Brayden Point each had a goal and an assist, Corey Perry had three assists, and Andrei Vasilevskiy made 27 saves for the Lightning, who won their final game of the preseason (1-4-0).
Rudolfs Balcers scored, and Spencer Knight made 26 saves for the Panthers, who finished the preseason 2-4-0.
Kucherov scored his first goal of the preseason, a power-play goal from the right face-off circle, at 3:51 of the first period to give Tampa Bay a 1-0 lead.
Balcers tied it 1-1 at 5:15 with a slap shot from the top of the right circle.
Namestnikov made it 2-1 with a one-timer from the bottom of the right circle at 12:15, then extended it to 3-1 by banging in a cross-crease pass from Perry on a 5-on-3 at 19:14.
He completed the hat trick at 7:30 of the second period off a pass from Ross Colton.
Aleksi Heponiemi came out of the right corner and scored short-side to cut it to 4-2 at 8:45, but Point tapped in his first goal of the preseason at 4:56 of the third period for the 5-2 final.
Kings 6, Ducks 3:Arthur Kaliyev had a goal and two assists to help the Los Angeles Kings to a 6-3 win against the Anaheim Ducks at Crypto.com Arena in Los Angeles.
Sean Durzi and Carl Grundstrom each had a goal and an assist for Los Angeles, which ended its preseason 3-3-1. Jonathan Quick made 23 saves.
Troy Terry had a goal and an assist for Anaheim in its preseason finale (4-3-0).
John Gibson made 16 saves on 19 shots in the first period before leaving the game because of an upper-body injury. Anthony Stolarz made 14 saves in relief.
Gabriel Vilardi scored a power-play goal 2:32 into the first period to give the Kings a 1-0 lead, and Kaliyev made it 2-0 at 11:08 with a wrist shot from the top of the slot.
Grundstrom scored from the top of the left circle at 14:17 for a 3-0 lead.
The Ducks scored three straight goals in the second period to tie it. Mason McTavish made it 3-1 at 3:57, Max Jones scored on a 2-on-1 with Pavol Regenda at 10:37 to cut it to 3-2 and Terry tied it 3-3 with a power-play goal at 14:45.
Durzi gave Los Angeles a 4-3 lead with a bouncing wrist shot from the blue line at 17:22.
Phillip Danault scored from inside the crease at 9:47 of the third period to make it 5-3, and Kevin Fiala scored on a one-timer in front at 12:24 for the 6-3 final.