The display turned in by Manchester City skipper Vincent Kompany against Manchester United during a 4-1 win last season at the Etihad Stadium is not one you forget in a hurry.

At the heart of Manuel Pellegrini’s back-four, the Belgian was an indomitable presence, shutting out the Red Devils forwards with athleticism, intelligence and an array of expertly implemented defensive skills. It was as close as you’d get to a template for how to play as a center-back against elite opposition and in the aftermath, Kompany was rightly revered as one of the finest defenders on the planet.

But the 28-year-old has toiled during City’s title defense and his display against Liverpool in the recent 2-1 loss couldn’t be further removed from the brashly confident one he showcased in the aforementioned duel with United. Naturally, it’s a regression that represents a pertinent concern for the Etihad club.

At his best, the City captain defends in an aggressive, front-foot style, mixed with a streak of maturity and assurance. But when you play in this position and deploy those aforementioned mantras, there’s a treacherous balance between a purposeful approach and plain rashness.

Sadly it’s the latter that has been on show as of late. Against the Reds, Kompany was tempted out of his defensive line on a regular basis by the subtle darting movements of Raheem Sterling—perhaps inspired by the exploits of Luis Suarez and Lionel Messi for Barcelona in midweek—hopelessly exposing his fragile defensive partner Eliaquim Mangala and an out-of-form Pablo Zabaleta.

It’s a chink in Kompany’s armoury that has occasionally been exposed throughout his time in the Premier League, but as of late it’s become an increasingly endemic and undesirable facet of his make-up. For a player who has previously exhibited an ability to marry tenacity and tranquility with such aplomb, something must have prompted this turnaround in fortunes.

After all, Kompany is no fraud of a defender, but the longevity of this lull suggests this isn’t merely a blip. Perhaps the stream of injuries that have punctured his time in England have coalesced to hamper his form at last? Perhaps the ambition that burned so prominently within him has abated after lifting two Premier League titles, an FA Cup and a League Cup as City skipper?

Perhaps. But the most obvious and most probable explanation is that Kompany’s downturn is a product of circumstance, and that’s something there for all to see in the cold light of day. City were naive at Anfield, naive against Barcelona and the personnel selected by Pellegrini in big games during his tenure implies this is a trait that’s here to stay.

The omission of the industrious James Milner against Liverpool was a peculiar decision given the unyieldingly dynamic qualities of the Reds, as was the decision to go 4-4-2. The lack of energy and tactical acumen was staggering, as players like Edin Dzeko, Samir Nasri and Yaya Toure sleepwalked through the contest. At a venue like Anfield against a team as effervescent and in-form as the Merseysiders, you simply can’t afford passengers.

Ultimately, those little instances of lackadaisicalness mount up and in a system like 4-4-2, eventually heaps a huge amount of pressure on the defenders. Against top sides and classy players—as was the case against Liverpool and Barcelona—that can make the back-four look very silly indeed.

This is clearly something that Pellegrini needs to address if City are to move forward under his tutelage.

But shifting focus back to Kompany—while the selections of his manager are doing little to alleviate the strain on the back-four—he’s a player who seems to be indulging in an timeless soccer cliche: if anything, he’s trying too hard.

His performances are resemblant of a captain who feels he needs to make a clear and definitive impact in a time of trauma. Kompany wants to inspire his teammates with thunderous tackles, intimidate opponents with towering headers and stir the crowd with enthralling pieces of play. But he’s erring on the side erraticism at this juncture and in amongst a group that’s striving for a precarious balance, his admirable intentions are hurting City.

Just look at John Terry’s man-of-the-match outing against Tottenham Hotspur in the League Cup final and a host of his exemplary performances this season. While the Chelsea man has a reputation for boldness and bravery, his recent efforts have been about emitting a calming aura, marshalling his teammates astutely and making mature decisions in critical moments.

It’s those kind of performances Kompany should be looking to take something from. In their current state City don’t need heroic, hurtling blood-and-thunder acts from their captain at the heart of a fragile defence, they need anecdotes of calmness to cling to as they look to salvage something from their season.

Much of that will depend on whether Pellegrini unveils a willingness to adapt in the second half of the campaign, but the individual must display some improvements too. Upcoming clashes with Leicester City, Burnley, West Bromwich Albion and Crystal Palace all represent an ideal chance to build some much-needed momentum.

Hopefully a refamiliarization with some fundamentals will help form the foundation for Kompany to reach the levels that saw him considered as one of the world’s best just 18 months ago.

Follow Matt on Twitter @MattJFootball