Here are five things the Flyers did right in those periods in particular. For the season as a whole, they've made early strides in each area but it's still a work in progress:

What are the keys to locking down the defensive zone so dramatically? Although fans inevitably point first at what the defensemen are doing, it's really all about how the team plays as five-men units or as penalty killing pairs of forwards and defensemen.

In two of the Flyers first eight games this season, they have held teams to a single shot in a period. They did it in the second period of the Dallas game last Saturday, and did it again on Thursday in Chicago. As a matter of fact, in the Dallas game, the Stars had only two shots over 38-plus minutes (unfortunately, one of them was a goal).

1) Layered defense. The Flyers forced Dallas and Chicago puck carriers not only to beat one man, but several. They made it hard to get through the neutral zone with any sort of speed Back pressure from the forwards is crucial. Without getting backchecking support, defensemen are forced to back into the D-zone as attackers come through the neutral zone with speed.

When the support is there, it's a lot easier to challenge and to make opponents force the play. Having a pair of strong two-way centers on the team in Sean Couturier and Kevin Hayes pays dividends in D-zone coverage because the center carries a lot of his own responsibilities from the dots down. Also, I've noticed less cheating (i.e., early exits looking for an outlet pass) by the wingers and more awareness of weak-side coverages on pinching D. Those are all early improvements from last year.

2) Good gaps and inside position. Your number one defensive weapon has always been your stick. Stick-on-puck plays, made consistently, short-circuit plays before they develop. When an opponent moves in, control his opponent's stick by keeping it within reaching distance, and keep yourself on the inside lane between the puck-carrier and the goalie to cut off the drive to the net.

3) Winning board battles. With the exception of Robert Hägg, the current Flyers starting six is not a particularly physical group. Hägg is not one of the better breakout passers but he is a sound defender. Typically, he is good at steering his check to the wall and pinning his man to the boards, to enable someone else to come dig loose the puck. You then have to win that battle, with help from the forwards.

4) Minimizing turnovers. Every team is going to have some turnovers on attempted breakouts and failed clears. The Flyers still have room to clean up these areas but they've been getting better. It's those turnovers exiting the defensive zone, in the neutral zone on attempted entries and up high in the attack zone that'll often come back on you as odd-man counterattacks the other way.

5) Pushing opposing attack to the perimeter. One thing that has been noticeable, which is at least partially due to adding a pair of experienced vets on the blue line, is that even when spending more-than-ideal time in their own zone, the Flyers generally haven't panicked. Even after an initial mistake on a breakout, if you push the other team to the perimeter and force them to attempt shots from the outside, you'll usually still be in good shape. It's after multiple failed clears that things commonly break down and end up in the net.