In any game, X’s and O’s are a given; in the Bruins-Maple Leafs series, it’s also about K’s and O’s.

In Game 1, the postgame sideshow was the scuttlebutt around Brad Marchand’s second kiss of the season that, indeed, began with K – as in Komarov, Leo that is.

The other “K” and “O” as in KO and OK, however, were front and center in Game 1 with the return of Rick Nash and Sean Kuraly who played much better than OK in contributing to drawing penalties toward a KO of the Leafs in that 5-1 final with three Boston power-play goals while the Leafs went 0-for-3 on the PP.

The third-period drilling by Nazem Kadri KO’d Tommy Wingels from the game and resulted in the league handing Kadri a three-game KO.

That resulted in Bruce Cassidy being OK playing Ryan Donato in his first playoff game Saturday, putting him on the third-line left wing with Noel Acciari and David Backes – and moving Danton Heinen to the right side on the fourth with Sean Kuraly and Tim Schaller.

“We tried Ryan over there,” Cassidy said pregame about the move, “I thought he did fine, but I think he’s better on the left side, whereas Danton can move a little more easily.”

“There’s not much you can do about it,” Leafs’ coach Mike Babcock said about both sides of the Kadri KO. “Let’s just get on with it. We went without a number of centers this year, let’s play.”

OK, coach: let’s play.

While the Leafs came out with more energy, it was the Black and Gold that was OK scoring the first goal for the second straight game when David Pastrnak scored at 5:26 on Boston’s first shot on Frederik Andersen. The Bruins had given up the first goal in each of the last five regular-season affairs.

Babcock was not OK with six Leafs public skating for a Bruins’ power play at 8:24 for too many men. If there is a turning point in the series to look back on, it might well be that penalty.

Kasperi Kapanen went in alone on Tuukka Rask, clanging the left post to deny the short-handed goal to tie the game. Seconds later, Jake DeBrusk put Boston up 2-0. Kevan Miller put Boston up by three at 12:13.

“There’s always a few,” Cassidy said in his opening postgame remarks, “when you look back at the game, probably moments of the game where you look back where things could have swung either way. I’ve got to believe it’d give them a lift to get a goal like that – shorties always do.”

That KO’d Andersen who gave up three goals in five shots in favor of Curtis McElhinney, who fared no better than his teammate.

Ron Hainsey attempted to KO Schaller in a feisty exchange but took an additional two minutes. On Boston’s eighth power-play opportunity of the series, Nash converted for his team’s fifth PP goal in two games just 10 ticks later at 15:00.

The only kiss in the game was a metaphoric good-bye type attached to a Kevan Miller check that KO’d Komarov from the game at 2:50 of the second 20. David Krejci applied the game’s KO punch just a minute later at 3:46, upping the lead to 5-1 after Mitch Marner dented Rask for Toronto’s first goal at 1:22. Tyler Bozak added the Leafs’ second at 9:02. James Van Riemsdyk the final Toronto tally late in the third.

Rask KO’d any Leafs’ comeback.

“[Tuukka] calms things down, Patrice Bergeron said, “he’s got that poise and he had to come out big – especially in the second.”

Pastrnak scored two for the highlight reel in the final 20 to complete his hat trick and a six-point game, best since Rick Middleton’s half dozen in 1983 against Buffalo and tied for best in team playoff history. A whopping 13 points for the first line in the 7-3 final; 20 in two games – OK!

“Terrific and terrific,” Cassidy said about the first line and Pastrnak. “I don’t think I can say any more.”

“Coaches talk to me every day through the whole season and especially playing with Bergy and Marchy – these guys know what it takes,” Pastrnak said about the keys to his epic night. “To be honest I wish every young guy got to play with these two players.”

The series moves to Toronto for Games 3 and 4 with the opportunity for Boston to KO the Leafs in Round 1 by next Saturday night in a possible Game 5.

“We’re not going to talk about it tonight,” Babcock said after about his team’s drubbing. “There’s no sense, obviously no one’s listening anyway.”

Sounds like KO’d language, eh?