Wallace is wrong, as shown by this screen shot.
Arsenal defender (red) is clearly keeping Dele Alli (white) onside, which led to
Harry Kane's sensational goal to make it 2-1
From the Telegraph article
Kane fires hosts ahead
What a finish. Harry Kane, that is magnificent. He bends in a 25-yard shot from wide of the box all the way around the goal and over Ospina. Absolutely incredible finish - he'll never finish one better. Luckily for Arsene Wenger, Dele Alli was offside in the build-up so he can blame that after the game, rather than his team going into meltdown. Again.