John Aldridge: Gunners visit will show if 'Pool are still up to standard at the back
Liverpool manager Jurgen Klopp has shifted his defensive line a few yards forward this season and it is not a plan that has been successful so far.
While his attacking trio of Mohamed Salah, Sadio Mane and Roberto Firmino provide the magic that helped Liverpool win last season's Champions League, the big factor that turned this team from trophy contenders into winners was their defensive improvement.
The signings of goalkeeper Alisson Becker and centre-back Virgil van Dijk's were key moments for Klopp and the organisation and calmness of Liverpool's defensive line gave them an edge over most of their rivals domestically and in Europe last season.
The Reds conceded just 22 goals in the Premier League last season and in Van Dijk, they have a defender who deserves to be recognised as the best in the business right now, but something changed over the summer and I'm not sure why Klopp has tinkered with what was a winning formula.
During the pre-season games and in the opening three competitive matches, Liverpool have not exuded the same coolness they showed throughout last season as we saw some frailties in the opening two Premier League matches against Norwich and Southampton and in the UEFA Super Cup game against Chelsea.
So far, Liverpool have got away with defensive errors, with young Trent Alexander-Arnold a target for opponents so far this season as they have got in behind him too often.
It has been a strange start to the season in many ways as Liverpool had a host of star names either injured or returning late from international duty and then had a long trip to Turkey for the Chelsea game that ended in a penalty shoot-out win in the Super Cup final.
The fall-out from that draining battle may have been a factor in the performance at Southampton, where a frantic last ten minutes so nearly saw Liverpool throw away two points after a horrible goalkeeping error from Adrian.
The concern for Klopp must be that Liverpool will not get away with defensive mistakes against Arsenal at Anfield on Saturday, with the Gunners boasting an attacking line that may be up there with the best in the Premier League this season.
Pierre-Emerick Aubameyang, Alexandre Lacazette and summer signing Nicolas Pépé should give Arsenal wonderful attacking options this season and their two wins to start the Premier League season should fill them with belief ahead of their trip to Anfield.
I always look forward to the clashes against Arsenal as they are a top club with great traditions and tend to come to Anfield showing real ambition.
That has backfired on them at times in recent years and they have been on the end of some heavy beatings, but Arsenal manager Unai Emery had a good transfer window and he will dare to believe his side are now ready too take on one of the Premier League's big-hitters and emerge with a point or maybe even more.
Arsenal are a much bigger club than Manchester City and Chelsea in terms of their history and fanbase, but they have fallen behind the clubs that have bought their way to success in recent years as their owner in America will not invest the kind of cash other Premier League clubs have ploughed into player recruitment of late.
There is potential for Arsenal to outscore a lot of their opponents this season and I'm sure they will be great to watch with that attacking trio causing havoc when they are on fire, but Liverpool will fancy their chances of getting at their defensive line this weekend.
Wins against Newcastle and Burnley in their opening two games were welcome for Arsenal, but we are about to discover whether they are the real deal when they take on a Liverpool team that are now proven winners.
We will also discover whether a Liverpool defensive set-up that has not looked comfortable this season can stand up to their first big test in the Premier League in what should be a contest to savour.