Everton’s inconsistency has been their main consistency this season. Well, that and injuries. Each time the Blues look set to kick on and banish their jittery early season form, their momentum is checked; and what frustrates most is that it is mostly their own doing.

For Roberto Martinez’s men to capitalise on this wide-open season, with Chelsea the only expected Champions League challengers displaying any genuine consistency, they must string together victories.

Although unbeaten in six, with three wins and three draws, it has been a run of games dogged by performances lurching from the good to the indifferent. The convincing Lille victory either side of disappointing draws against Swansea and Sunderland typifies current form.

The Lille win also marked a significant though, in all likelihood, barely noticed first of the season, however. On the surface, it appeared like any other routine home win, but it was the first time this term that those in royal blue had collected three points without Seamus Coleman on the pitch.

Until Leon Osman, Phil Jagielka and Steven Naismith capped a pleasing team performance to cement first place in Group H, the Toffees possessed a win percentage of zero without their first choice right back.

Scoring in the emphatic Europa League opener against Wolfsburg, as the hosts clinically dispatched a German side enduring a similarly slow start to the season, Coleman departed in the closing minutes with an injury.

The fullback missed the next five matches; Everton won none of them. His goalscoring return against Aston Villa coincided with a return to winning ways for the Blues. In total, the influential defender missed six matches out of eight following his injury. As you might have already guessed, the two wins in that eight-game period arrived in the two matches featuring Coleman.

Though injury has hampered his statistical output to this point, Coleman still sits tied as the division’s top-scoring defender, joining teammates Leighton Baines and Phil Jagielka (and a host of other defenders) on two goals for the season.

In this regard, the resurgence of Baines helped temper the loss of Coleman. Once again, the primary source of creativity after a slight drop in the previous campaign, Baines has delivered an outstanding 12-goal contribution in 15 matches, scoring three and assisting another nine.

Much like his fellow attacking fullback, a welcome knack for affecting matches at both ends of the pitch is just one of many reasons as to why Coleman is such a key figure in this side, outscoring every other Premier League defender with eight goals since the start of last season.

However, to focus solely on his goalscoring exploits would be a disservice to his overall contribution. From his baptism of fire in Lisbon, when the young defender found himself out of position and out of his depth on debut, to the present day, the Everton right back is easily the most improved player in the squad.

His all-action style provides an attacking threat on the right, one capable of easing the pressure on the excellent Baines on the opposing flank, but he also balances out the team.

When Coleman is absent, his importance only increases. The lack of alternatives is an obvious factor, but rarely has the loss of one player created such disruption, especially in the fullback area. When the Republic of Ireland international is unavailable, it often leads to an entirely unbalanced right flank - regardless of who replaces him and who plays in the midfield role ahead of them.

In fact, even when Coleman is present, he can still find his influence dimmed by others. Despite a rather useful outing himself, Aiden McGeady seemed to hamper Coleman in the recent draw at Sunderland. Only once McGeady departed and Steven Naismith freed up the flank by drifting infield did Coleman begin to impact on proceedings.

Then outside of his ability to bring a balanced feel to the side, there are the defensive aspects to reflect glowingly upon. Eased into the side under David Moyes, first used sparingly as a needs-must-attacking-alternative at right back, the former Sligo Rovers player learnt most of his early trade on the right of midfield.

Initial success soon faded, though, leaving the inexperienced and inconsistent youngster suffering in his unfamiliar midfield surroundings. In the end, it was the return to his preferred position which truly kick-started Coleman’s Everton career.

Teething problems occurred, nonetheless, which led to many doubters writing the tenacious fullback off, believing him destined for the long line of young pretenders failing to seize their opportunity.

A notable slip at Fulham springs to mind, toward the tail end of 2012. Ball watching at the far post, Coleman allowed Steve Sidwell to steal in and snatch a point for Fulham in a match Everton dominated from first whistle to last.

It is to Coleman’s credit and undoubted determination, though, that his form and all-round game has reached such heights since then. You can count subsequent errors on one hand (at most).

Blessed with recovery pace – such a useful tool when facing the jet-heeled wingers of the division - and surprisingly strong in the air for a player of relatively short stature, there are many strings to this Irishman’s bow.

David Moyes used to list Nigel Martyn as his best signing, with the veteran goalkeeper a bargain buy who secured player of the year in his first season, but nowadays it is almost impossible to look beyond the meagre £60,000 spent on Coleman as the definitive buy of the Moyes era.

He has transformed from an attack-minded but slightly naive prospect to one of the most accomplished and consistent right backs in the Premier League, perhaps even the standout right back.