Maybe not mathematically but Arsenal have guaranteed the lead in the group if we look at it from a logical aspect. Because there is no way PSV are closing the gap of 5 points in only 2 matches. Maybe PSV might revenge this loss in their home match against Arsenal. But Arsenal should be able to defeat Zurich on the final match week and qualify as the leader anyway.
Arsenal were in control from the start to the end in this match. PSV were able to find only a few goal attempts and couldn't score. But the score was still risky of course as Arsenal won by 1-0. Despite that incredibly high dominance Arsenal couldn't score more goals. We saw more usual starting eleven players entering in the second half but the score still didn't change. On the other hand Arsenal got what they wanted and that's what matters now.