To be honest, i actually thought he was pretty poor last night when he came on!!
Wasted the ball a lot and should have had a better touch a few times when he was in on goal.
He also looked knackered again after about 20 minutes and you could hear Koeman shouting at him at one point for not closing a player down on the touchline.
HOWEVER.....I am a massive Gerry fan and even when he isnt playing well he makes things happen. Bringing him on allowed us to counter more quickly and their defence were scared of the pace on both wings with him and Bolasie going at full pelt.
He badly needs to become more consistent but I recon he should keep his place for the Boro game at the expense of Ross