Pre-match trade was slow at the Sea Bay fish and chip shop outside The Valley, the queue virtually non-existent compared to first-day crowds in recent years. "You don't know what this division is like," said the owner. "I'll just have to wait and see." She could have been speaking for the club, who are enduring equally uncertain times. Phil Parkinson's side won but could easily have lost.
Charlton and most of their fans are unfamiliar with this division. This is the first time since the 1980-81 season that the Addicks have been in League One – or the third division as it was known back then. But after decades away from the bottom two divisions, it has only taken them three years to drop to this level.
In 2007, they were relegated from the Premier League. Last season they finished bottom of the Championship but Parkinson is still in charge.
Echoes of a more successful past are close at hand. It was under their much-loved manager Alan Curbishley – nicknamed Curbs – that they had become well-ensconced in the top flight. His departure in 2006 started the club's decline.
For this season, their shirts bear a new sponsor, 'krbs' – for Kent Reliance Building Society. Say it out loud and it sounds like Curbs. You can imagine Parkinson's response when he saw that.
If Charlton are to get themselves out of this mess they will look to players like Christian Dailly – a free transfer and now 35 years old – and his teammate at the opposite end of the age spectrum, Jonjo Shelvey, who is 17 and the club's youngest ever first-team player.
He has been a target of Chelsea but chose to sign his first professional contract in south, not west, London
The two combined for the first goal, Dailly heading in from Shelvey's corner after 21 minutes, and two minutes later Nicky Bailey found the top corner. Wycombe, promoted from League Two last season, looked lost until Chris Zebroski halved the deficit with a header two minutes before the interval.
Five minutes after the break Miguel Llera, with 11 stitches from a clash of heads, scored what turned out to be the winning goal. But Zebroski slipped a shot under Rob Elliot with 17 minutes to go as Charlton, groggy with exhaustion and nerves, had to endure a late Wycombe response.
Parkinson said: "It was a great win for us. At the end, people had to throw themselves in the way of the ball. It showed what we will have to contend with in this division."
And if Charlton can contend with life in this division, then maybe the Sea Bay can too.