Chelsea achieved the remarkable on foreign soil in May but there was still something strangely unfamiliar about this. A team which has spluttered too often away from Stamford Bridge in this competition mustered a victory by a margin to send a message to the group, even if plenty about this occasion was deceptive. At first glance this looks a thrashing but against a side still pinching themselves about being in the Champions League at all the holders will not be hoodwinked.

Emphatically as it all ended, with Nordsjaelland running out of steam in the last dozen minutes and wilting at the end, this was anything but a walk in the Parken. If the majority of chances created by the arena's adopted home side were only fleeting sights of goal, usually snuffed out by a blur of blue as a Chelsea player dived in to intercept, then there was genuine anxiety when Joshua John, the Danes' outstanding loanee from Twente, curled an attempt towards the far corner when the holders' lead was still at its most slender. Petr Cech, diving to his left, summoned a staggering save to fingertip the ball on to the post and Nordsjaelland's chance was gone.

"It was a crucial save," said Roberto Di Matteo. "The Danes had nothing to lose at the time and, with the scoreline only 1-0, it was a dangerous time.". He could at least depart encouraged that this own team is winning away again in Europe.

Penalty shoot-outs in Munich aside – and that success in May was one to cherish above all others – only Benfica had been beaten on Chelsea's travels since Carlo Ancelotti's team prevailed in Copenhagen two seasons ago. This team will travel to Donetsk for a potentially critical fixture later this month with confidence pepped and as early leaders in Group E. They will need to be better there than they were here but the reality that Shakhtar drew at Juventus was a reminder of how tight this section could prove.

Chelsea will still be confident of progress, particularly if their attacking unit is permitted to flourish as they eventually did here. Juan Mata was their inspiration, the Spaniard having been irrepressible since he was granted a short break during last month's international window to recharge his batteries. His burst upfield just after the half-hour went unnoticed as Nordsjaelland's rearguard were panicked by Fernando Torres's dispossession of Enoch Adu, the striker shifting the ball on to Frank Lampard who in turn slid it into space to his right. Mata finished on the gallop, putting the ball beyond Jesper Hansen.

The early exchanges had threatened a cricket score with Victor Moses – on his first outing in this competition – forcing Jores Okore to nod against his own post and Torres twice close to registering personal reward. Yet, without John Terry to bark orders across their back-line, sloppiness crept into the visitors' game. This was a landmark occasion for the Danes, a home debut in the Champions League albeit in an arena some 15 miles from their distinctly cosier Farum Park. The club has existed in various guises over the years and endured scandal and financial uncertainty aplenty and this game was seized upon as reason for celebration. The crowd in attendance was more than Farum's entire population. They could be proud of their team's efforts until the closing stages.

John was a nuisance down the left, with Ashley Cole doing well to snuff out Kasper Lorentzen's attempt in front of goal as carelessness offered the locals sights of goal. Their best opportunities were chiselled out just after the hour, John skimming a shot into the side-netting, Nicolai Stokholm forcing the goalkeeper to push another attempt clear and Mikkel Beckmann twice spurning presentable opportunities.

Then came Cech's save, with the substitute Mario Ticinovic's follow-up well blocked, before Chelsea roused themselves to respond.

The goals came at a canter thereafter. Oscar had seen one harshly ruled out, the Croatian official having opted against playing an advantage, before David Luiz curled a fine free-kick in off a post with Hansen static. "We collapsed after that second goal," said the Nordsjaelland coach, Kasper Hjulmand. "We'd been playing well, creating chances, but in the end it looks stupid on the scoreboard, 4-0."

Mata's second was slid home after he emerged from the clutter on the edge of the area and Ramires' tap-in from Oscar's cross added gloss to the win.