Barry was joined on deadline day by fellow loan arrival of Chelsea striker Lukaku, and the Manchester City midfielder believes Roberto Martinez's introduction of the powerful striker helped change the game at Upton Park.
"He gave us something different in the second half," he said. "First half we were just probing and couldn't really break them down. We didn't really threaten them much.
"Rom came on and gave us a different type of player up there; he scared them with his pace and allowed us to get space in front of them. He was getting the ball and turning and helping us break."