It has been a thoroughly impressive season for Charlton Athletic since they returned to Championship via the League One play-offs - one that will have far surpassed many expectations.

Lee Bowyer's side were made convincing favourites to be relegated come May 2020 and it was easy to see why. Upon their second-tier return, the Addicks had a myriad of off-field problems, key men had jumped ship, including Joe Aribo and play-off hero Patrick Bauer, and even Bowyer's future remained incredibly uncertain.

Had you offered Charlton survival at the start of the season, the vast majority of fans will have taken as I'm sure would have most of the squad and coaching staff.

But with 15 games now elapsed, focus has started to turn towards the top end of the table.

Just three points currently sits between themselves and Bristol City, the side who occupy the final spot in the play-offs at the time of writing, so talk of a top-six place and hushed whispers of back-to-back promotions have started to be heard over the opening months of the season.

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And why not? They have already beaten Leeds United, pre-season promotion favourites, as well as taken points from West Brom, Nottingham Forest and Fulham.

However, and I don't want to put a dampener on things for The Valley faithful, their most important game yet is coming this weekend - and here is why.

Whilst only three points currently separates Bowyer's men from the top-six, they remain just ten points clear of the relegation zone, a place where many expected them to be scrapping this season.

A large gap for now, but with so many games still left to play, it is an advantage that can vanish quickly.

And a relegation scrap is somewhere weekend opponent's Millwall currently dwell, sat in 17th place, but they could move to within a point of their local rivals with a victory at The Den on Saturday.

So really this is a clash that should be a matchup between two sides on the backfoot, and whilst that is not necessarily the case, it is what makes the match so crucial.

The Championship is one of the most unpredictable leagues in world football. Things can change wildly within a few games and Charlton must be wary - a relegation battle is still not out of the question.

And if that battle comes around, it is winning the 'nine-pointers' against the likes of Millwall, who are likely to join them in that battle, which will prove crucial come the end of the season - rather than wins against Leeds et al.

Last season we saw Bolton Wanderers win three of their opening four games before plummeting down the table to be emphatically relegated.

Whilst it is a shorter time frame, the message and warning remains clear. Bolton saw off the likes of West Brom and Derby in that campaign, but were still sucked into the scrap, after failing to pick up points against those also battling the drop.

A top-six challenge should not be ruled out at The Valley but at the same time, Bowyer and co. must remain wary of where the most important battles will be fought.