It had been 33 years since the Flyers played the Islanders in the playoffs. Now they’re going to play four times this week. Too much Semyon Varlamov and too many struggles in their own zone have the Flyers facing a 1-0 series deficit. Here are some observations.

Caught flat-footed. The Flyers were chasing the game throughout the first period, which was an annoying habit they had during the regular season. If not for Carter Hart, the Islanders could have been up 4-0. Eventually, they were.

What’s next? Game 2 is Wednesday. Note the 3 o’clock start time. It’s the first of three playoff games that day.

No shot. The Flyers had only four shots in the first period, none by the forwards in the final nearly 12 minutes. They steadied the ship in the second, but couldn’t dent the scoreboard.

Semyon says. Varlamov has a shutout streak of 136 minutes, 20 seconds. He made 29 saves, including some gems on Kevin Hayes and Travis Konecny. Hayes had a breakaway, but he couldn’t get a shot on Varlamov.

Paging Dr. Coots. Head coach Alain Vigneault gave Sean Couturier the nickname Dr. Coots during the season because the quickest way to fix an ailing player’s game was to put him on Couturier’s line. Well, it’s Couturier who needs treatment for the first time in about two years. The Konecny-Hayes-Joel Farabee line was the Flyers’ best. Couturier’s line, except for a couple bursts by Jake Voracek was silent.

Greene was money. Veteran defenseman Andy Greene scored his first playoff goal in 10 years with a point shot that beat Carter Hart to the glove side. Greene’s last goal was in the 2010 first round against the Flyers’ Brian Boucher in the only game that series won by New Jersey. Greene was plucked from the Devils at the trade deadline by current Islanders general manager Lou Lamoriello, the GM who signed him to his first NHL contract.

Didja have it? Greene was 45-1 at DraftKings to score the first goal. He was also 45-1 to score the last goal. DraftKings would have paid both ends had the game ended 1-0.

Empty feeling. So desperate were the Flyers to generate offense, Vigneault pulled his goalie with more than seven minutes left down 3-0. The Islanders proceeded to score a 200-foot goal off a funky bounce.

NBC ya. Keith Jones stepped in for deposed NBCSN analyst Mike Milbury and provided terrific analysis, even from the studio in Connecticut. He noted Alain Vigneault ought to consider changing lines when the Flyers were under siege in the first period. Not long after, Claude Giroux was moved back up to the top line with Sean Couturier and Michael Raffl moved down.

Numerology. Teams that have lost Game 1 of a best-of-7 have comeback to win just 31.1% of series. For the Flyers, that number is 38.5%. More substantially, the Flyers have not lost consecutive games since Jan. 7 — a span of 37 games.

Here’s a thought. The Canadiens hammered the Flyers 5-0 in Game 2 of the first-round series, and Philadelphia responded with consecutive shutouts. Expect some lineup changes. Morgan Frost, anyone?

Quoting. “The first period was probably the worst first period we’ve had in the bubble,” said Giroux. “In the second and third, we generated more offense and played better. But the top players gotta play better. I’m obviously one of them. We gotta get going here.”