England v Australia this weekend is a tough one to call even though it's being played at Twickenham.
England haven't played at full strength since their 30-3 hammering by Wales in the Six Nations decider at the Millennium Stadium in Cardiff last March and have a lot to improve on.
Australia have won only three of their past 10 matches but are showing signs of improvement under their new head coach Ewen McKenzie.
So which areas will be pivotal to the outcome of Saturday's match, and where might England seek to gain an advantage?
The scrum must be a talking point...
England will feel they have the advantage at scrum time, as do most top teams when they play the Wallabies, having smashed Australia in that phase in the past.
Remember, the laws have changed. As a result the team that's more technically gifted has a big advantage, so if England have worked even harder with forwards coach Graham Rowntree on how to take advantage of the new laws, then England will profit.
Scrummaging is not a traditional Australian strength. It's a big embarrassment because there's no real excuse not to be good, given the size and strength of props James Slipper and Ben Alexander, and hooker Stephen Moore. It is a collective thing but it does start in the front row.
Australia only won 63% of scrum ball on their own feed in the recent Rugby Championship - the worst of the four teams.
If the England front row of Mako Vunipola, Tom Youngs and Dan Cole can dominate their opposite numbers, psychologically it will go a very long way to securing a victory for England.
At the other set-piece, the line-out, Australia won 100% in the same fixture last year. Their success rate was still 86% in the recent Rugby Championship. England were down to 83% during the 2013 Six Nations, so Stuart Lancaster's team need improvement there.
Avoiding the Aussie jackals
Australia's Michael Hooper is a very effective open-side and will be very destructive in slowing down England's quick ball.
For England captain Chris Robshaw to nullify him, he will need huge support from his team-mates, as he did when they played New Zealand last autumn.
England need to move the point of contact from the rucks, no one-out hits. That will make it too easy for Hooper to jackal any isolated runners by getting over the ball and stealing it. Both Vunipola brothers are extremely explosive runners but need close support to produce the quick ball.
All the England forwards tackle well and have a high percentage tackle success, as it should be because it's generally close-quarter tackling.
England's perceived weakness could be in the backs where centre Brad Barritt normally operates so well. There's a big responsibility on Billy Twelvetrees to lead that defensive attack, he must nullify the talented runners he and the England backline are going to face.
Applying the pressure
My tip for England's midfield would be to blitz Australia centre Tevita Kuridrani, because he drops balls under pressure.
Robshaw cannot allow Wallabies fly-half Quade Cooper an easy run out; he's capable of tearing to shreds the best defences in the world. Pressure, pressure, pressure is what he has to impose on Cooper.
For all the good play we've seen from England wing Chris Ashton so far this season, he has to show himself and team-mates that his defence has been sorted, otherwise it will be stressful out there.
Beware the Wallabies backs
The balance of power in attack for me goes to Australia. Will Genia, Cooper, Israel Folau, Kuridrani and Adam Ashley-Cooper are exceptional attacking talents.
McKenzie has chosen Matt Toomua at inside centre ahead of Christian Leali'ifano, which surprised me given how good a kicker Leali'ifano is.
Having the mercurial Cooper alongside the more physical Toomua, two fly-halves who play differently, is an interesting mix. It is a sort of Jekyll and Hyde pairing but they combined well against New Zealand last time out.
Neither England wings are tall and will be susceptible to the kick-pass from Quade Cooper to the 6ft 5in Folau.
Folau is one of the most exciting players in the game right now, he's scored seven tries in 10 Tests, including those two on his debut against the Lions.
His all-round skill-set makes him dangerous in all situations from anywhere on the field. I don't believe you can set out any special strategy to nullify him: just make your tackles when he's in your channel if you can.
What about England... they've got a new strike weapon haven't they?
I'm really looking forward to seeing Marland Yarde playing, he has impressed so far this season.
Yes it's a step up but he, like all newbies, will have no baggage and can play with freedom - if he can overcome any nerves.
The London Irish wing strikes me as a player who loves to score more than anything but he mustn't be consumed by that desire. If there's a pass for another player to score to be made by him, he must execute and not try to do it all himself.
Joel Tomkins should play on instinct, not get bogged down with too much detail of how England play. By that I mean the Saracens centre shouldn't be thinking about doing anything different to the way he normally plays; it's all about what he can do and be effective with and without the ball.
The selection of Lee Dickson ahead of Ben Youngs and Danny Care at scrum-half indicates to me England are going to try and up the tempo of their game.
Youngs and Care look to break themselves whereas Northampton man Dickson looks to get his hands on the ball early and release quickly to a first receiver.
Last time Dickson didn't stay as number one very long, he wasn't influential enough in his play for England - Stuart Lancaster needs to settle on his half-backs soon.
Your nine and 10 generally dictate how the team play - where on the field and when to do what. Tinker with these two positions and you're tinkering with the whole team dynamic. Dickson is a good choice, he has been solid this season and can really up the tempo of this team.
So who's going to win?
Australia's best opportunity to win is to catch England cold and play at a tempo the hosts will struggle to acclimatise to. That means continuing where they left off against New Zealand last time out.
I'm excited by the possibility of England adopting a smarter gameplan - looking to generate quick ball, attack the gainline with the good ball-carriers they have and dominate the breakdown.
Teams have to be patient at times; there will be periods where you won't have the momentum but when England do, it's all about making and taking the opportunities you create. Make good decisions, backed up by great execution.
It really is a close game to call, but I will go for England. I believe they have changed the way they want to play and will have a gameplan to produce quick ball and score tries.