With the club in a state of flux following Ian Holloway's resignation, the Eagles had something of a "free hit" against Arsene Wenger's men—they weren't expected to win, so the team was under no pressure.
It's those games where title pretenders can slip up and identify themselves as fallible and weak, but Giroud played a big part in ensuring the Gunners stay relevant, classy and feared.
Here, we'll analyse what was an astonishingly complete performance from the former Montpellier man..
Arsenal set up in a now-customary 4-2-3-1 formation, with Mikel Arteta and Mathieu Flamini in holding midfield roles. Mesut Ozil was a No. 10, Aaron Ramsey spread right and Santi Cazorla played as an inverted left-winger.
That left Giroud to lead the forward line on his own, win headers, link play and provide a goal threat. That's the job of the complete forward in 2013, and the 90-minute expose the Frenchman put on really hammered home what a well-rounded player he's become.
His role changed throughout the game and he adapted seamlessly, showing elite awareness and a real understanding of what his team needed for him.
The first hiccup—and cause for adaption—arrived in the form of Flamini's early injury.
Arsenal look more confident and much safer with Flamini on the pitch. He finished the 2012-13 season with four fantastic months in Milan, and since signing he has truly shored up the deeper midfield areas at the club.
He defends counterattacks superbly, tracks runners expertly and shields his improving defensive line. With the midfield locked down, Giroud can be freer, more expressive in his linkup and take risks around the edge of the box.
That's what he's been doing recently and he's found some joy, but it's no coincidence that the first game Flamini missed (Borussia Dortmund) is the first Arsenal lost since he's joined.
With Ramsey and Arteta dropping into holding midfield, Giroud adopted a calmer, safer approach in his decision-making to expose Arsenal to the fewest amount of quick counterattacks possible.
Flamini's dominance (or absence) directly affects the game Giroud can play.
As the Gunners built up a head of steam and dominated the ball, the right side began to emerge as the major threat to Palace's clean sheet.
Serge Gnabry, on for Flamini, provided a tricky presence and won the penalty to open the scoring, and later Ozil gave Dean Moxey fits down the touchline.
Giroud has developed a penchant for hitting the near post when crosses come in and has already netted goals against Aston Villa and Tottenham Hotspur in this fashion. That run has become common knowledge to opponents now, and as a result they tend to overcompensate and overcommit in covering it.
WhoScored counted 10 shots for Arsenal, but they were oh-so-close to creating another six or seven clear-cut chances.
Had the Gunners' midfield runners used his near-post run (and double-marking) to their advantage by breaking off their runs and finding a yard of space they could have scored another two; had Giroud's crosses when drifting off to the right (as pictured) been a little better, it could have been six.
Spreading wide, testing full-backs, hitting the near post, attracting markers to create space for others have been hallmarks of both Giroud's performance against Palace and of his 2013-14 season.
Giroud's goal to seal the 2-0 win was a thing of beauty, even if it pales in comparison to Jack Wilshere's against Norwich or Patjim Kasami's at this very ground five days previous.
The Frenchman took in a long pass from Nacho Monreal and flicked it on for Ramsey, who was steaming forward.
The in-form midfielder took the ball 30 yards and held it, attracting two defenders and creating space for another runner in the middle.
Giroud smelled blood and sprinted 50 yards from his previous position to the edge of the box and beat Damien Delaney for pace and desire. Ramsey's clipped cross was at a perfect height, and the Frenchman headed home.
He started the move, he finished the move; the lay-off for Ramsey was perfect and his desire to get on the end of the subsequent cross admirable. Factor in the fact he'd been closing down Palace's back line at the top of a 4-4-1 formation since Arteta's sending-off in the 65th minute and it's easy to see why he looked exhausted come the final whistle.
A complete performance from a rapidly improving player. This is the Giroud that Wenger thought he'd signed last summer.