West Ham face a major test of their improvements to crowd control at the London Stadium after drawing Chelsea in the EFL Cup.
The Hammers' move to their new ground has been beset by problems, culminating in fights breaking out among supporters during the recent defeat by Watford, while there was also crowd trouble against Bournemouth.
The club have already relocated 200 disgruntled fans, beefed up segregation and vowed to improve stewarding but still have no police presence in the stadium due to the lack of a suitable radio system.
In their programme notes prior to the Wednesday night's third-round meeting with Accrington, co-chairmen David Gold and David Sullivan wrote that they expect the issues "to be resolved in the coming weeks".
West Ham were handed 'low-risk' early fixtures as they settled into their new home, with Bournemouth and the Hornets the first visitors and no London rivals due until Arsenal head to Stratford in December.
But Dimitri Payet's last-gasp free-kick to beat League Two Stanley means a derby against Chelsea next month and an earlier-than-expected test of the security and stewarding.
The Hammers have been beset by crowd trouble in 2016 with the Manchester United team bus attacked ahead of the last game at Upton Park.