Carlo Ancelotti says Everton have not abandoned their principles, but rather tweaked their approach, after a run of four straight Premier League victories amid an injury crisis.
Lucas Digne, James Rodriguez, Allan and Richarlison have all been out over the course of the last month, yet the Toffees have won their last four league games, following a run of just one win from seven.
To cope with a growing absentee list, Ancelotti switched to a solid defence of four centre-backs, and Everton have not conceded from open play during their winning run.
West Ham and former Toffees boss David Moyes are the first visitors to Goodison Park in 2021, with Ancelotti able to welcome back Richarlison for Friday's meeting.