Arsenal scored two second-half goals to sink Cardiff City at the Emirates Stadium.
Pierre-Emerick Aubameyang's penalty and Alexandre Lacazette's strike meant Nathaniel Mendez-Laing's late goal was only a consolation.
The game was Cardiff's first since the disappearance of striker Emiliano Sala, and both teams took part in a minute silence before the match.
Image via Premier League
The first half-an-hour saw virtually no chances for either team, with Arsenal dominating the ball, as expected.
But Alexandre Lacazette was denied a penalty, when Sol Bamba stuck a leg out in the box, the Frenchman went over but the referee waved away any appeals.
Image via PA
Cardiff were performing well at the Emirates and they were attacking with a threat.
Callum Paterson shot wide of Bernd Leno's post early into the second-half, but the Bluebirds were impressing.
Bruno Manga brought down Sead Kolasinac and the referee awarded a penalty this time.
Aubameyang made no mistake from the spot; firing home past Neil Etheridge to put the Gunners in the lead.
Soon after, Lacazette broke through the Bluebirds' defence before firing past Etheridge from inside the box.
Cardiff, who performed bravely all game, did give the Gunners a scare.
Mendez-Laing turned smartly in the box and fired past Leno into the bottom corner.
The Managers
Arsenal head coach Unai Emery: "We are happy. In the first-half we didn't deserve to go in winning and in the second-half we played better, controlled the match better and created more chances.
"We started well in the first 20 minutes then I was not surprised with the performance as Cardiff worked very well.
"We struggled a lot in the match but it's very important to get the three points. We know each match is difficult and we are happy - the difference is small details."
Cardiff City boss Neil Warnock: "They should've had a penalty in the first-half and I spoke to Bruno (Ecuele Manga) at half-time so for him to dive in like that again, I'm just really disappointed. The players have to think about their responsibilities, it was just amateur."