Cardiff - Unai Emery collected his second victory as Arsenal manager thanks to a fine strike from Alexandre Lacazette in a 3-2 success at Cardiff on Sunday.
Emery's men had threatened to surrender two more Premier League points as they twice squandered the lead, with Neil Warnock's Cardiff exploiting old failings for the Gunners.
But, despite making hard work of seeing off the promoted Welsh side, Arsenal sealed maximum points with Lacazette's late strike to record only their second away Premier League win since December.
Shkodran Mustafi headed Arsenal ahead before Victor Camarasa equalised in first-half stoppage-time as Emery received another intensive lesson in the strengths and weaknesses in his squad.
There was more of the same in the second half as brilliance from Pierre-Emerick Aubameyang restored the lead before another defensive aberration allowed Cardiff to draw level for a second time through Danny Ward.
At times it appeared the new Arsenal manager would witness old issues undermine his side as they were pegged back, leaving Emery in no doubt about the strengths and weaknesses in his squad.
If Gunners fans hoped the end of Arsenal Wenger's reign would cure the brittleness of their team, they received a clear reminder in the Welsh capital that Emery has much work to do to add the requisite resilience to his side.
Twice his men went ahead against the Premier League new-boys and twice familiar defensive failings allowed Warnock's men back into the contest.
Yet it was ultimately an afternoon of success for Emery, who saw the Gunners' persistence rewarded with Lacazette's emphatic strike nine minutes from full-time.
There were other encouraging signs, too, not least the set-piece threat that brought the opening goal and might have led to another.
With just 12 minutes on the clock, Mustafi out-jumped everyone to power home a header from Granit Xhaka's cross and, in the second half, only a save from the Cardiff goalkeeper Neil Etheridge prevented a carbon copy goal.
Chief among the Emery;s concerns was the continued struggles of goalkeeper Petr Cech to deal with the Spanish manager's commitment to build from the back.
Twice in the opening eight minutes Cech made a mess of dealing with back-passes and, on the second occasion, Harry Arter fired over when he should have opened the scoring.
There were defensive headaches too which came to the fore in first half stoppage-time when Xhaka's poor pass was intercepted, Nacho Monreal failed to execute a simple interception from Joe Bennett's cross and Camarasa spun to find the roof of the Arsenal net.
More defensive weakness on 70 minutes allowed Ward to head home unmarked off the base of the woodwork after Aubameyang had restored Arsenal's lead six minutes earlier, bending a superb shot past Etheridge after being teed up well by Lacazette and Mesut Ozil.
But Arsenal's superior individual ability finally won the day when substitute Lucas Torreira fed Lacazette, whose turn of pace allowed him to rifle a winner inside the near post past Etheridge.
Still there was time for Sean Morrison to head a superb chance just over for Cardiff as Arsenal did their best to give away the lead for a third time, leaving their manager with much to reflect on during the international break.