Mikel Arteta quickly influenced change at Arsenal, but the result did not follow as Chelsea stole a London derby victory on Sunday.
It was little wonder Mikel Arteta had his head in his hands - and that was before Chelsea grabbed a late winner in a 2-1 victory at Arsenal on Sunday.
The new Gunners head coach had seemingly produced a masterclass, outmanoeuvring Frank Lampard a week on from the Chelsea boss' own breakout tactical display away at Tottenham.
But then Bernd Leno, one of Arsenal's more consistent performers in this miserable season, failed to intercept Mason Mount's deep 83rd-minute free-kick and instead left an open goal for Jorginho, who might have been sent off six minutes earlier and was fortunate to escape a second yellow card for wrestling Matteo Guendouzi to the ground.
As has so often been the case for Arsenal this term, worse was still to come.
Tammy Abraham led a counter-attack, took a return pass from Willian and shot through Leno's legs, clinching another stunning away London derby victory for the Blues.
On a day when optimism filled the air at Emirates Stadium, when the fans roared and the players ran - yes, even Mesut Ozil - Arsenal were left with that all-too-familiar sinking, losing feeling.
Arteta's grand plans to prove Arsenal are "the biggest football club in England" - a bullish pre-match claim - looked more realistic than most would have imagined for an hour of his home coaching bow.
The man who helped hone Pep Guardiola's dazzling Manchester City side made swift progress with a disharmonious Arsenal outfit.
The front four were especially dynamic, Ozil joined by Pierre-Emerick Aubameyang and Alexandre Lacazette - a trio Unai Emery could not get working in unison - alongside the speedy Reiss Nelson.
Nelson stayed high and wide on the right, as Arteta's Leroy Sane of sorts, while Aubameyang and Lacazette traded the Raheem Sterling role on the opposite flank, the former scoring as the latter harried hapless Chelsea.
Lampard's defensive three, which was certainly a horse for the Spurs course but faltered against Southampton, quickly looked a one-trick pony.
Chelsea's boss hooked Emerson Palmieri before half-time and switched back to a 4-3-3, yet still his side struggled, Fikayo Tomori bullied by Lacazette at right-back until Tariq Lamptey's impressive introduction shortly before the hour mark.
Ozil, so often derided for a perceived lack of effort, led Arsenal for distance covered until late in his 76-minute shift. Jeered as he made way against City in the Gunners' previous home game, there were cheers as he ambled off this time, the lead still intact.
Meanwhile, the tireless Aubameyang made three tackles, two clearances and two interceptions to go with his early opener.
But this was still Arsenal in 2019. They ended the previous calendar year beaten 5-1 at Liverpool and, while there were certainly now positives, their latest reverse is still perhaps even more painful.
Calum Chambers started well before injury, yet surely only investment will fix a defence that battled for a time but eventually gave way to the type of performance we have come to expect from a David Luiz-Shkodran Mustafi combination.
The late collapse leaves Arsenal 12th, nine points behind Chelsea in fourth, having lost three straight home top-flight matches for the first time since 1977.
Arteta's primitive tenure may have briefly brought hope, but pessimism was evident again as the stands emptied in the final minutes and Arsenal failed to win for the 14th time in 15 games in all competitions.