A 3-0 away victory at a ground where the might of Manchester failed to win proves Arsenal have the style and grit of true title contenders.
Despite their four-point lead at the start of December, doubts will persist over Arsenal's ability to capture the English Premier League title and end their eight-year trophy drought.
A recent history filled with high-profile failures, near misses and flattering to deceive has ensured that Arsenal are rarely taken seriously as true contenders.
The skeptics usually point to a lack of grit, an absence of the determination to grind out results in tough places. But this season's Gunners are as well-stocked as any team in the grit department.
A plethora of late goals is ample proof of a group that never gives up probing for scoring chances. This characteristic was exemplified in the recent 3-0 demolition of Cardiff City, featuring two goals after the 85th minute.
The newly promoted upstarts had already bested Manchester City and held current champions United to a point. Those sterling results were built on the foundation of a packed and rugged defensive structure that had afforded some of the EPL's marquee maestros little time to weave their magic.
Cardiff have harassed, harried and pressed the division's elite and ruthlessly exploited their opportunities from set pieces. If this pragmatic combination sounds disturbingly familiar to Arsenal fans, it should.
It is the same dynamic that has often been kryptonite against manager Arsene Wenger's brand of stylish and expansive passing football.
In recent seasons, Stoke City—once the standard-bearers for using physicality to frustrate technique—have given Arsenal fits. They packed the midfield to clog passing lanes, while pressing and taking a savage approach to tackling the man in possession.
They routinely stifled Arsenal's creative flair away from the comfortable confines of the Emirates Stadium. That allowed the Potters to seize their chances from set pieces thanks to a robust brand of aerial power.
But before Stoke routinely "roughed up" Wenger's boys, it was Sam Allardyce and Bolton Wanderers using overt physicality to frustrate some of the Frenchman's best teams.
The not-entirely-accurate critique that Arsenal shy away from the physical side of the game has dogged Wenger for years.
However, his current squad are shattering that myth.
Not only can this season's table-toppers absorb the physical blows, they are not above dishing out a few of their own. It is a streak of genuine tenacity that goes right through the spine of the team.
Laurent Koscielny and Per Mertesacker are as uncompromising as any centre-back partnership in the country. In midfield, Mathieu Flamini and Jack Wilshere are the terriers who won't hesitate to leave a mark on the opposition.
Even Mikel Arteta and Aaron Ramsey have given Arsenal greater solidity. Neither is easily brushed off the ball by those who think that a bit of muscle is all that is needed to best these Gunners.
Up front, Olivier Giroud—the big man who often plays like a finesse striker—still possesses an undeniable nasty edge to this game. Giroud takes a lot of punishment from centre-backs, but he metes out his fair share in return.
The point is that Arsenal can no longer be bullied and considered a soft touch. Why is this so important?
Because once Wenger's players make it clear that they won't surrender the physical battle, their superior style is able to dominate. And this is a team with style in abundance.
The quality of this season's passing and movement has approached the lofty standards Wenger set during his glory years at the club. It stems from a chameleon-like midfield that embodies fluidity and forward-thinking guile.
Arsenal's clutch of playmakers can create chances against anybody, but what is most impressive is how hard they are ready to work to do it.
The performances of Santi Cazorla and Mesut Ozil against Cardiff serve as prime examples. Cazorla has not quite hit the heights of his superb debut campaign, but he remains a player with the class to influence any attack.
He often cut a periphery figure on the left in Cardiff, while Ozil and Wilshere created patterns in the middle. Cazorla never stopped working to press from the front, win the ball and make runs to create space for others.
He never stood idle and eventually his toil allowed his contributions to grow. If the little Spaniard's graft was impressive, it was nothing compared with Ozil.
The languid schemer has had his critics at times this season, with this author one of them, but he must have gone a long way to winning over a lot of doubters last Saturday.
This was a game during which he appeared destined to wilt under the hustle-and-bustle atmosphere created by Cardiff's supporters and their high-energy play.
Instead, the opposition's stubborn resistance only made Ozil try harder. His movement was constant and imaginative, as he looked for ways to circumvent a nine-man defensive barrier.
His effort was rewarded with a first-half assist, a nice cross to set up Aaron Ramsey's opener. Then in the second half, with Arsenal holding a narrow lead, Ozil did what he is paid for.
He used his creative touch to decide a close contest in the Gunners' favor. His threaded pass was slammed home by Flamini to seal the points.
In previous seasons, when teams have challenged Arsenal the way Cardiff did, there hasn't always been the same determination to bypass heavy numbers.
The likes of Samir Nasri and Andrey Arshavin would often appear to adopt a "this isn't our day" attitude against such spoiling tactics.
But Ozil, Cazorla, Wilshere and Ramsey are focused enough to bide their time and keep working to fashion chances rather than surrendering to frustration.
That is a tremendous quality for creative players to possess, and it speaks to what is different about this Arsenal team. The common criticism in the past has been that the Gunners have to be at their best to get results.
This squad has regularly proven its resolve to still claim points when they are below par.
They were not at their best against Southampton at home, or even in the Welsh capital. Yet they kept working and found ways to win both games.
They were very, very poor for long stretches away to West Bromwich Albion back in October. Yet they still managed to graft their way to a point.
That credible championship contenders win when they play badly is an overused phrase, but a true one nonetheless.
The Gunners ability to do it, forged during their 10-match unbeaten run to fourth place last season, shows they are for real. A few wins against the big boys are all that remain for Arsenal to silence their critics, but this is not a team that will fade away as they have in previous years.
During their barren run, Arsenal have often failed to match some grit to their style, or vice versa. Now they have the right blend of mettle and flair to stay at the forefront of this title race all season.