Manchester United got their Premier League campaign off to the best possible start with victory over Chelsea on Sunday

Sky Sports News reporter James Cooper provides expert analysis and insight following Manchester United's "ruthless" start to the new season…

Ole Gunnar Solskjaer may have been widely quoted for his promise of a "ruthless" transfer window that didn't quite come to fruition, but it would not have escaped his notice that his players showed their ruthless side on Sunday.

As the Deadline Day disappointment dissipated, the question that was then asked was: 'How do you replace the 42 goals of Romelu Lukaku from the past two seasons without actually replacing him?'

2:54 Highlights from Manchester United's 4-0 win against Chelsea in the Premier League Highlights from Manchester United's 4-0 win against Chelsea in the Premier League

Those of us that were lucky enough to tour with United during the summer were given glimpses of the post-Lukaku era as punishing training sessions gave rise to greater pace, strength and endurance.

United may not have started as fluently as Chelsea but they out-ran, out-thought and ultimately out-battled them with the movement of Anthony Martial and Marcus Rashford catching the eye.

Anthony Martial and Marcus Rashford were on target in United's 4-0 win over Frank Lampard's side

Solskjaer's preferred 4-2-3-1 formation means it is not down to one focal point or one player to do all the running; everyone runs. The formation does not just benefit the attacking thrust and its cutting edge, but it also affords greater defensive security too.

Maguire's leadership key

Quite rightly, accolades were paid to Harry Maguire for an impressive debut, but with Paul Pogba and the eager Scott McTominay in front of him, he was rarely exposed. Quite simply it's a system that allows the world's most expensive defender to find his feet in the goldfish bowl of Old Trafford and in a formation where players seem to know their roles and responsibilities.

Ole Gunnar Solskjaer had promised a "ruthless" summer, but delivered only three signings

United would have liked to have brought in greater quality in the window but in Maguire, Aaron Wan-Bissaka and Luke Shaw, they may have three of England's future backline. Throw in goalkeeper David de Gea, who will have grown in confidence again thanks to a solid display and a clean sheet, one of last season's better players in Victor Lindelof and structurally Solskjaer's defensive foundations immediately look more secure.

Maguire will lead by example, but his leadership is also key to the direction United want to go in with the centre-back also adding a voice to what can often be a quiet defensive unit if Ashley Young is missing.

Harry Maguire kept a clean sheet on his United debut following his £80m move from Leicester

Pogba's role

The manner of United's victory over Chelsea may have been the surprise of the weekend, but it also hinted at the key role Solskjaer wants Pogba to perform this season after a pre-season of uncertainty. Flashes of brilliance from the Frenchman proved enough to push home the advantage over Chelsea. His consistency and fitness are perhaps the major concerns for those who look at last season's finish rather than this season's start as a barometer to the true Pogba factor.

McTominay's progression and passion, Dan James' pace and integration and Axel Tuanzebe's inclusion on the bench show the path Solskjaer is laying out ahead even before the potential of Mason Greenwood is mentioned.

Paul Pogba impressed in the win over Chelsea, providing two assists

United traditionally open a season strongly - they have only lost twice on the opening day at Old Trafford in the Premier League era. But immediately they look a stronger, younger, more robust and mobile proposition. The onus will be on keeping players fit in the face of a more demanding workload and the absence of a couple more quality players who could have helped shoulder the burden.

The next challenge is a visit to Wolves. Solskjaer could not find a way past them in the Premier League or the FA Cup last season, but knows he has a squad of players who seem to have rediscovered their hunger and belief.