Pablo Fornals and Michail Antonio had put West Ham ahead twice as their 100 percent start to the campaign ended due to goals from Gallagher.
Vieira, who has admitted that the club is eager to add a striker to its ranks before Tuesday’s transfer deadline, at least has faith that the England Under-21 international can make a difference throughout the season.
“He has the ability to stay calm within the area,” de Gallagher said.
“He is a great finalist, he has a lot of energy and he works very hard for the team.
“When he’s in that kind of situation, he’ll score us goals.
“I am very satisfied with the two goals we scored, of course, but I never had any doubt that we scored goals, it was only a matter of time. We were unlucky the last couple of times we played.
“I think it was a well deserved point. We played well, especially in the second half.
“I am really satisfied with the character we show today and we have to build on that performance.”
Additional PA reports.