Another terrible pass from Cech at the start of the second half put his team under pressure, but Hoilett wasn't able to punish the visiting keeper as he cleared the crossbar from 28 yards out.
Arsenal did eventually regain the lead in the 62nd minute when Pierre-Emerick Aubameyang completed an excellent passing move by firing the ball into the bottom corner of the net. Monreal, Bellerin, Guendouzi and Xhaka were booked for Arsenal, whereas Cardiff City's Camarasa, Junior Hoilett and Harry Arter also saw themselves get into the referee's book.
Aubameyang scored the second for Arsenal with a sublime curling effort from outside the 18-yard area.
His continuous exclusion from the starting eleven has therefore been a surprise to many as he has been tipped to provide the steel cover for the defence, a quality that has been missing for Arsenal in the past years.More news: Simona Halep suffers upset at US Open to Kaia Kanepi
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Cardiff were one of the most popular picks to be relegated before the season started.
Both the Gabonese global and Frenchman were still seeking their first goals of the season.
Messi made it 1-1 in the 16th minute - weaving his way past, around and through four defenders before firing a pinpoint strike past the goalkeeper - followed by the own goal (Jorge Pulido) in the 24th.
Opting to start the two strikers alongside each other, Aubameyang and Lacazette were given the opportunity to lead the line from the off. Still, the Gunners now have six points on the board for the season.
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.
According to reports, Unai Emery has personally stood in the way of allowing Emile Smith-Rowe to be sent out on loan this season.