The Capitals skated away with an overtime win in Game 1 against Toronto. (Patrick Smith/Getty Images)

Brace yourself. On Thursday night, the Washington Capitals fell behind the eighth-seeded Toronto Maple Leafs by two goals before the chair in front of my big-screen TV was even warm from the squirming of my nervous rear end.

You can watch the Caps for two weeks and never see one of them whiff, shank or snap their stick on a shot. Those things are frequently signs of pressure and tension and the tight hands and poor timing that accompany those afflictions. In the first period alone, my notes said, “Backstrom fans, Shattenkirk mis-hits, Shattenkirk whiffs, Williams shanks and Williams whiffs.”

By the time the Caps won in overtime on a top-shelf shot barely under the crossbar by their least likely sniping threat, Tom Wilson, I muttered, “Am I really ready for this?”

It’s doubtful that I am, and it’s unlikely that many Washingtonians have any idea what we are in for. That 3-2 Washington win will, in retrospect, register near zero on the tension, panic, joy and insanity meter before this season is over.

If the past half-dozen NHL postseasons are any indication, then in the coming weeks the Caps will play nearly eight overtime periods, face three season-ending elimination games, trail in a series four times and face a Game 7 twice.

And that’s if they win the Stanley Cup. Those are the averages of the winners.

The Caps host Game 2 on Saturday against the young, fast and brilliantly coached Maple Leafs, a team that has no chance on paper but appears to think its odds are better on ice.

Oh, and did I mention the Washington Wizards start their NBA playoffs Sunday against the Atlanta Hawks, also at Verizon Center?

Over the next two weeks to two months, Washington sports fans are going to be knocked on their ears, flipped on their heads and sent screaming — with joy or despair — into the streets more times than they can imagine. The District has never had two teams in the playoffs at the same time with expectations nearly as high and talent as good as these Caps and Wizards.

One of the biggest obstacles that confronts both the Caps and Wizards is that few of their central stars have any experience of the odds, which seem emotionally astronomical, that must be ignored if they are to be overcome in the postseason.

Perhaps Justin Williams, nicknamed “Mr. Game 7,” can tell the Capitals about the Stanley Cup he helped the Los Angeles Kings win in 2014, when he scored nine goals and had 16 assists in 26 playoff games. Yes, 26 games — bring your lunch and dinner, D.C., because this Capitals thing, if it works out right, is going to take a while.

To win that Cup, the Kings had to come back from a three-games-to-none deficit in the first round. In all, the Kings won seven elimination games when their season might have ended. They won three Game 7s — all on the road. They came to the rink six times trailing in a series. They played 10 overtime periods.

So, folks of the District, prepare for that five-hour, triple-overtime skate-of-the-living-dead Caps game that Washington absolutely, positively must win because there’s a decent chance it will happen. When the Blackhawks won Stanley Cups in 2015 and 2013, they had to win a triple overtime game both years .

A couple of months ago, long after a game, Caps Coach Barry Trotz talked about all the amazing postseason comebacks in sports in the last year or so — the Patriots in the Super Bowl, the Cubs and Cavaliers coming back from three-games-to-one deficits to win the World Series and NBA Finals, as well as Clemson’s comeback to beat Alabama in the college football national championship.

“We need to understand that, to get what we want, we’ll probably have to overcome something like that at least once — maybe more,” he told me. “Over and over, in every sport, that’s just the nature of the beast.”

So please don’t tell me how easily the Caps will handle Toronto just because they “escaped” with a Game 1 win. Trotz called the game “a really good wake-up call.” Oh, yeah? Only if the Caps stay awake because, as Nicklas Backstrom said, “We have to be better.”

Now, I keep hearing how well the Wizards match up with the Hawks because Atlanta won’t be able to handle Washington’s wonderful guard tandem. Well, how effective will the Wizards’ frontcourt be against Dwight Howard and Paul Millsap now that backup center Ian Mahinmi is injured and Marcin Gortat has played poorly for weeks?

Wizards fans are a trifle giddy because Washington almost won 50 games for the first time in 38 years. The Hawks were 43-39, a record the Wizards would envy in most seasons of the past four decades.

Both the Caps and Wizards have the ability and regular season résumé to roll into their postseasons with serious expectations. But both lack one vital piece of firsthand experience: an understanding of what a long and often dispiriting fight they are about to encounter — even if things go well.

In boxing terms, both are certain to get hit in the mouth, see their own blood, find themselves on the canvas and, at least once, take a standing-eight count. To get where they want to go, they probably will be counted out — by others.

If the Caps and Wizards think they will be the first Washington teams to get past the second round of the playoffs in nearly 20 years — or in the case of the Caps, go all the way to the end of the line — they need one sobering historical reminder.

When everyone tells you that you are dead, that your dreams were just a bad joke and that failure is almost certain, that’s not when your playoffs end.

That’s when they start.