Sam Allardyce must prioritise Everton system that suits both Gylfi Sigurdsson and Wayne Rooney

Sam Allardyce looks on from the stand during the Premier League match between Everton and West Ham United at Goodison Park on November 29, 2017 in Liverpool, England.

So far this season, Everton have failed to get the best out of two key men; that must change.

Everton's English striker Wayne Rooney celebrates scoring their second goal during the English Premier League football match between Everton and West Ham United at Goodison Park in...

One issue has been present throughout Everton's early optimism and subsequent disappointment in the opening months of this season - and it remains a problem now.

How can the Toffees get the best from both Wayne Rooney and Gylfi Sigurdsson?

It is a question Sam Allardyce must now answer as he steps into the Goodison Park job, having seen Ronald Koeman and David Unsworth both fall short.

Sam Allardyce looks on from the stand during the Premier League match between Everton and West Ham United at Goodison Park on November 29, 2017 in Liverpool, England.

The new man's first call will undoubtedly be to decide that there must be a system to suit both players, with the decision to drop either the club's talisman or their record signing unthinkable.

Rooney delivered his best performance of the season as he netted a hat-trick against West Ham United on Wednesday, playing from a deeper midfield role.

But that was in a midfield three and Sigurdsson was still forced to play in an unnatural wide left position.

Everton's Icelandic midfielder Gylfi Sigurdsson is introduced to supporters on the pitch ahead of the UEFA Europa League playoff round, first leg football match between Everton and Hajduk...

Not yet this season have Everton fans seen Rooney and Sigurdsson working effectively in tandem.

If this side are to realise their immense potential, Allardyce must discover a set-up that suits both players and the team.

Register for EVERTON team updates

Register for HITC Sport - Daily Dispatch