Arsenal eased to a 4-0 victory against Swansea City at the Liberty Stadium with goals from Olivier Giroud, Alex Iwobi (2), and Alexis Sanchez.

But if the emphatic scoreline made it look like an easy game for Arsene Wenger’s men it wasn’t – certainly not the first half of the first game for the Swans under highly-regarded new boss Paul Clement.

Arsenal withstood impressive movement and pressing from a fired-up home team in the opening 45 minutes with only Giroud’s goal separating the sides at the break.

However the North Londoners’ extra quality shone through in an open and attacking second half as they eased to victory with a further trio of goals.

Gunners’ boss Wenger made four changes from the FA Cup victory over Preston, with Petr Cech, captain Laurent Koscielny, Mesut Ozil and forward Alexis Sanchez all being recalled after they were rested for the match at Deepdale.

Benched were David Ospina, Ainsley Maitland-Niles, Lucas Perez and Alex Oxlade-Chamberlain.

Clement also made four changes, from the FA Cup defeat at Hull City with former Arsenal man Lukasz Fabianski, defender Alfie Mawson, midfielder Wayne Routledge and striker Fernando Llorente returning in place of Kristoffer Nordfeldt, Mike van der Hoorn, Leroy Fer and Borja Baston.

Was it really only four years ago a buoyant Swans team walked away from Valencia’s imposing Mestalla Stadium with an unlikely win against one of the giants of Spanish football in the Europa League?

If a week is a long time in the game then four years is an eternity. Gone are manager Michael Laudrup and the influential Huw Jenkins – whose name the vociferous travelling support chorused loudly from the upper tier of the cavernous city centre stadium. Jenkins is now a figurehead chairman, with the real power residing with the new American owners.

And with it went Swansea’s reputation as a footballing side and a judicious well-run club in question. Gone are the European sojourns – replaced by a more prosaic – but far more important – fight for Premier League survival.

In the years laden with a League Cup triumph and Europeans trips the Swans were renowned for their work-rate and intensity of their pressing, which through instability brought on by a number of changes of management, and a lack of a coherent strategy – on and off the pitch – has led to a far more laissez-faire approach.

It was clear in the early stage the impressive Clement has already convinced his charges of the benefits of hard work in closing down the opposition.

And when the opponents are Arsenal, it tends to lead to a more attacking ethos. If you add good technique and impressive movement to the home side’s armoury it was no wonder Wenger’s men were under the cosh in the early stages.

What was also evident was that the highly promising Mawson – the 22-year-old former Brentford centre half - was under strict instructions to play out from the back.

With 11 minutes gone Kyle Naughton showed his willingness to shoot from the right, which Cech did well to tip around the post.

Moments late Wayne Routledge worked the ball to Fernando Llorente, who fired narrowly over from outside the box. Nobody could accuse this Swansea team of lacking confidence.

A bright rainbow loomed over the Liberty Stadium under slate-grey skies as the heavens opened on a cold winter’s afternoon in South Wales you could be forgiven for wondering whether the crock of gold was more likely to be spent in this transfer window by the home manager rather than Wenger – despite having the more gilded – but vastly under-performing side recently.

It took until the half hour mark for Arsenal to have a shot through Sanchez, which Fabianski comfortably gathered.

But it was their extra class which eventually shone through eight minutes before half time through Olivier Giroud’s close range strike.

The goal was arguably harsh on Swansea - but what could not be disputed was the excellent through-ball from Ozil to Aaron Ramsey.

The former Cardiff man fired across goal to no avail, but the hard-working Sanchez collected it and fired it back into the box. Ozil then headed the ball at Fabianski, who could only parry it before Giroud lifted the ball into the roof of the net to make it nine in matches and 11 in all.

There was as much relief as joy – and certainly none of the over-elaborate celebrations from Giroud as there were after his late equaliser at Bournemouth – which was perhaps a recognition that there was a lot of hard work to come.

There was drama two minutes before half time when Ki Sung-Yueng appeared to be felled in the box. However, referee Lee Mason made the right decision by declining to award a penalty. For good measure he then booked the South Korean forward for diving.

Despite the howling crowd it was the right decision. It was also a brave one.

But as he blew for half time the expected waves of derision were not forthcoming – perhaps a reflection his judgment may have been correct.

The second half opened with both teams looking to attack – an indication that a draw was no good to either in their ambitions.

It wasn’t for Arsenal as they found themselves out of the top four before kick off, neither was a point particularly useful for Swansea in their fight against relegation.

A concerted spell of Arsenal attacking – mostly played out in the Swansea area failed to deliver the second goal. And with Arsenal there is always the feeling a second – or third, or fourth goal – is invariably needed to make the game safe.

However, moments later Iwobi’s effort saw his team go 2-0 up. It was the least they deserved for their incessant attacking in the second half – even if his deflected looping shot off home captain Jack Cork was a tad fortuitous in evading Fabianski’s despairing backpedalling attempt.

Arsenal then made it 3-0 after Iwobi collected the ball in a wide position and fired across goal – with Naughton taking a decisive touch to send the ball past Fabianski with 20 minutes remaining.

Three minutes later Sanchez hit a fourth as the second half turned into a rout.

It was unfair on Clement – but he will know more than most after his surprising and unjustified sacking from Derby last term – that football is unfair.

Swansea City: Fabianski, Sung-Yueng, Mawson, Llorente (Borja), Dyer (Fer), Routledge, Sigurdsson, Cork (McBurnie), Naughton, Fernandez, Kingsley

Arsenal: Cech, Gabriel, Koscielny, Sanchez (Welbeck), Ramsey, Ozil (Perez), Giroud (Oxlade-Chamberlain), Iwobi, Monreal, Mustafi, Xhaka