Cech entered the game having made the most saves of any Premier League keeper in the opening three rounds but every mistake he makes is another argument in favour of giving new signing Bernd Leno a chance to show what he can do. The France global also set up Pierre-Emerick Aubameyang to make it 2-1 in the 62nd, making a strong argument for why the two forwards should be starting together regularly.
If they were level at the start of the second half, they weren't after 62 minutes following a fantastic goal scored by Pierre-Emerick Aubameyang, putting Emery's side in front once more.
Despite Cardiff's impressive display, Arsenal went ahead for the third time.
"We are continuing to work on the combinations". In fact, Xhaka's error lead to Cardiff's first goal.
However Lacazette had the final say when he thundered a strike past Etheridge to get the goal his performance deserved.
Former Liverpool and Switzerland player Stephane Henchoz also recently spoke out about Xhaka and Shaqiri's celebrations, telling Blick: "The double-headed eagle has no business in the Swiss national team".
Aubameyang has been criticised of late for squandering chances in front of goal, particularly two sitters against Chelsea, but netted today and seemingly flourished with Lacazette leading the line.
"The Premier League is a different game and you have to move and change accordingly", Warnock explained.
The Gunners boss was impressed by the attacking midfielder in pre-season and is expected to hand him some game time this term. Arsenal need to sort these defensive problems out soon.
Arsenal looked good on the ball but Emery still has plenty of work to do defensively as they gave too much space for the Cardiff forwards.