This game had been a tight affair before the goal, with both teams having chances but none being particularly clear-cut.
That changed in the 29th minute, thanks to some good interplay from Alex Iwobi and Nacho Monreal on the left flank which started the move.
The Spanish full-back got to the by-line and drilled the ball across to Lacazette.
He controlled the ball, and in one movement turned nicely and swept the ball in to the bottom left corner of the net, to continue the run of goalscoring form he is enjoying.