The Frenchman struck with a 65th-minute header to seal a tight encounter which never really took off, although he was grateful that a glaring miss four minutes later did not prove too costly when goalkeeper Wojciech Szczesny blasted a clearance straight at Loic Remy and saw the ball run just wide of the post with time running down.
Arsene Wenger's men enjoyed long periods of possession at St James' Park, but were rarely able to make it count, and it took a set-piece from Theo Walcott, who was otherwise largely anonymous, to present Giroud with his big chance.
Newcastle might have gone in at the break ahead had Szczesny not tipped over Moussa Sissoko's blistering strike or had Mathieu Debuchy's header not come back off the crossbar.
However, they were unable to sustain the pressure as they slipped to just a second defeat in 10 league outings in front of a crowd of 52,161.
Pardew was able to draft Cheick Tiote back into his starting line-up after suspension with Hatem Ben Arfa making way, but opposite number Wenger was not so fortunate as he lost Mesut Ozil and Aaron Ramsey to injury and Thomas Vermaelen and Nacho Monreal to illness.
The Newcastle manager, just as he had done against Chelsea in November, set out to frustrate the Gunners with a five-man midfield, but saw his side concede space and possession in the early stages as they found themselves pinned back.
However, for all they created half-chances, keeper Tim Krul did not have a save of note to make with Tomas Rosicky shooting straight at him from 20 yards with 27 minutes gone.
Santi Cazorla extended the Holland international three minutes later with a deflected effort which dipped nastily in front of him, but Giroud curled harmlessly wide 12 minutes before the break with Mike Williamson and Fabricio Coloccini, with the support of full-backs Debuchy and Davide Santon, limiting the Gunners to long-range efforts.
The Magpies had a chance to take a 12th-minute lead when Arsenal target Yohan Cabaye floated the ball over the top into Debuchy's run, but the defender could not control with just Szczesny to beat.
The Frenchman shot wide from a similar position 13 minutes later after again getting in round the back to collect Cabaye's deep free-kick, but he was to go significantly closer as the whistle approached.
There was barely a minute of stoppage time remaining when Vurnon Anita surged forward and picked out Cabaye, whose long-range strike was blocked by Laurent Koscielny, only for Sissoko to latch on to the rebound and force Szczesny to tip over a piledriver.
From the resulting corner, Debuchy headed against the underside of the crossbar and the Gunners managed to smuggle the loose ball away as referee Lee Probert blew for half-time.
After a tentative start to the second half, Anita caused panic in the Gunners' defence when he clipped a cross towards lone striker Loic Remy, although between them Szczesny and his colleagues managed to keep the Frenchman at bay.
The visitors were seeing plenty of the ball, but once again were able to do little with it with Mathieu Flamini's speculative 57th-minute effort, which sailed high and wide, as close as they came to troubling Krul as the game approached the hour-mark.
Pardew made his move with 28 minutes remaining when he sent on Ben Arfa for the tiring Yoan Gouffran and charged him with the task of running at Arsenal.
But it was the visitors who went ahead three minutes later when Walcott floated a free-kick into the box and Giroud got ahead of Williamson to glance it past Krul.
He should have doubled his tally within four minutes when, after Walcott saw his initial effort blocked by Krul and his follow-up headed off the line by Debuchy, the ball fell to him with the goal at his mercy, but he could not hit the target.
Newcastle's pushed for a late equaliser and came close when Szczesny hammered the ball at Remy and looked on helplessly as it ran just wide.
Source : PA
Source: PA