He said: “It’s been a difficult couple of weeks and it was so important to get the first goal.
“With the results that we’ve had it was good to get back to winning ways.
“It makes a big difference going a goal up rather than going a goal down and to get the early goal it was good for us and it set the standard for the rest of the game.”
Welbeck could actually have scored five minutes earlier – accidentally.
A Seamus Coleman clearance rebounded off him and against the post.
Iwobi, on his first Premier League start, should have added to Arsenal’s flying start a minute later but he shot weakly at Robles.
Everton actually had the first effort of the match, when Coleman stabbed the ball just wide. Muhamed Besic, after some neat footwork, also pressed David Ospina into a save.
But Arsenal should have been awarded a penalty in the 35th minute, when Besic clearly brought down Chile forward Sanchez.
But the Gunners did not need referee Mark Clattenburg to punish hosts Everton – they did that themselves.