Arsenal manager Arsene Wenger has warned West Ham that it could take at least two years for them to settle into their new surroundings at London Stadium.
After 112 years at Upton Park, West Ham moved to the bigger-capacity stadium in London ahead of the 2016-17 season, but it has coincided with the club struggling for form in the Premier League.
West Ham suffered a humiliating 5-1 loss to Arsenal on Saturday as they dropped to 17th in the table, only a point above the relegation zone.
And Wenger, who oversaw Arsenal's relocation to the Emirates Stadium from Highbury in 2006, believes West Ham must be allowed time to get used to London Stadium.