The first week of finals often throws a shock to the system. Seemingly infallible teams can fall to earth, and new favourites can emerge seemingly overnight.

AFL semifinal week is the perfect encapsulation of the concept. Both Brisbane and the Hawks look somewhat bulletproof, while the qualifying final losers look ripe for the picking.

However, as Liverpool great Bill Shankly was once reported to say "form is temporary; class is permanent".

Port Adelaide and GWS have had to make use of their second chance in this year's race for the flag, and will be hoping Shankly was on the money all those years ago.

"You know you get the opportunity to get a double chance," Port Adelaide coach Ken Hinkley said in the wake of his side's 84-point loss to Geelong last weekend. 

"Unfortunately, we're going to have to use it. We didn't want that to be the case — we didn't set out for that to be the case. We now have that actual reality in front of us." 

The double chance isn't just for show either. Five premiers have made their way to the grand final the hard way since 2000.

However, the most common fate for the first week's losers is to win once more before succumbing in a preliminary final.

However, over the past decade the number of qualifying final losers going out in straight sets, and making it to the grand final, has increased.

But to make it any further the Giants and Power have to have that class shine through against two of the league's hottest teams.

Unpacking Port's defensive holes

Geelong have long been recognised as one of the more creative teams around certain parts of the ground, particularly in relation to how they set up around clearances and in defence. They regularly change up the members and makeup of their on-ball unit, as well as their positioning.

Leading into last week's qualifying final, Hinkley was firm about what faced his team.

"I'm going to be really strong — we're going to play our game. If you watch Geelong and watch them play they have, you know, they do have a lot of tricks that they throw around at you, so we're going to make sure we do our best to not get distracted by that."

Despite Hinkley's pregame statement, some of these tricks seemed to throw Port off balance.

Take this early game centre bounce for example. Geelong seemingly ignores their Port counterparts while setting up for the tap.

The Cats rotate around the circle, aiming to cover the defensive side of the centre while allowing Tanner Bruhn to attack from deep behind the contest. Geelong stays spaced while the Power seemingly get sucked into the inside, trying to trap Atkins or the ball.

The end result was a mark by Blicavs — the ruck — in the forward 50. This use of space and movement was emblematic of their approach and Port's issues.

Elsewhere, they threw an extra number into stoppages at times, prioritising the defensive side of the stoppage. Geelong seemingly ignores Jason Horne-Francis here, letting him run at the ball before Shaun Mannagh wraps him up.

The Cats alternated how they treated the young Port star — tight marking followed by no marking, pushing him into the defensive side of contests or just running past him in the "hit zone". Making Horne-Francis and Connor Rozee work hard defensively seemed to be a goal of their attack.

These stunts — alongside others — forced Port's clearance game off balance. This probably wasn't helped by an injury to Zak Butters when coming into the finals Port had the best scoring from clearance differential in the league.

Against Geelong they lost the clearance score by 54 points. That's big, once-in-a-season type numbers. 

When you lose by 84 points there's usually more than one reason. However, their approach to clearances — and general around-the-ground contests — looked to be a clear issue.

Around the ground, it looked like Geelong prepared better at the drop of the ball, especially inside the Cats' forward 50. While Port registered more intercept marks than the Cats across the game (21-18) and contested marks (14-10), Geelong dominated ground balls 91-77.

Often it seemed multiple Power players went airborne or were caught flat-footed while the Cats moved dynamically around the aerial contest. The result was several won balls through the middle and classy crumbed goals throughout the game.

Hawthorn presents a chance for the Power to reset. They aren't as strong as the Cats are through clearance, and their defensive philosophies are more predictable around the ground — but perhaps more effective.

Despite external commentary from some quarters, the Power's clearance score differential isn't dramatically different between the top eight (+8) and bottom ten teams (+12). They don't have the profile of a flat track bully.

Everyone at Alberton will be hoping it was a one-off bad game, and that experience will shine through against a young Hawthorn side.

Fine margins decide finals winners and losers

It's easier to find reasons when your team loses by a lot than when it loses by a little. For most of Saturday's qualifying final, it looked like the Giants would get the week off and the Swans were gearing up for the long path to the grand final.

If you listen to Sydney coach John Longmire speak directly after the match, you might be even more mistaken as to who actually won the game.

"I just probably wanted to firstly acknowledge GWS. I mean they were fantastic. Like they were fierce. In the tackle, in the contest, they were really hard and clean." Longmire said after their close win.

Despite leading for 121 minutes and four seconds of the game, the Giants are gearing up to host the dangerous Lions while the Swans now get the week off.

Despite the Giants playing a "fantastic" game, it was not infallible. GWS dominated the game around stoppage, outscoring the usually deadly Swans and stopping their dangerous midfield from piling on the points.

They also managed more tackles across the game — a sign of their clear determination around the ball.

But as the game wound to its conclusion their focus slipped when trying to get the ball up the ground. The Swans scored 43 points from turnovers generated in their front half compared with 23 from the Giants.

The difference was even more stark after half-time. The Giants failed to kick a goal from this source in the second half while the Swans kicked two goals in the third quarter and three more in the final term. That includes Joel Amartey's sealer, all coming from a stellar Nick Blakey ball win against two opponents on attacking wing.

On the rebound from Blakey's spoil, it appeared like the Giants were slightly bent out of shape — too focused on their attacking game. The Giants are a side that looks its most dangerous when it is counter-attacking quickly. That free-flowing disposition comes with risks.

Overall the Giants' defence is strong, but defending against their own turnovers is perhaps their one weakness — especially against other good sides. Good sides, unsurprisingly, tend to set themselves up better to attack from turnovers than those on the lower rungs of the ladder.

Dominating field positions is critical to most teams in modern footy. Working out how to avoid getting trapped inside your defensive half is a priority for most sides.

Sydney finished the year second in scoring from front half turnovers — behind only the recently farewelled Carlton. The side in third? Well, that's Brisbane — the Giants opponents this week.

Brisbane has long been one of the strongest sides in the competition at attacking from front half intercepts. However, the Giants have largely avoided this trap in their two victories this year.

The Giants will be hoping that they can avoid it a third time and work towards redemption — plus an extra week of footy.