The Hawthorns outfit have not won a match since Pepe Mel took over from Steve Clarke in early January, and are only out of the Premier League relegation zone by goal difference.
Fulham, who will be under the stewardship of new boss Felix Magath for the first time, are four points further back at the foot of the table, and Brunt knows a victory would be huge for both sides.
"It has been a while since we've had a game this important," he told the club's official website.
"If we win, we can hopefully put a little bit of distance between ourselves and the other teams at the bottom. It would lift everyone, too - but Fulham will be saying the same thing.
"It's a big game for them as well. They've just changed their manager so I'm sure they are going to be fighting for their lives.
"Hopefully, the week we've spent in Spain, where we've practically all been living together, can help us going into this game.
"We have good spirit. We've also got people coming back from injury who might be able to help us out in the next few games.
"We've only won four matches all season and if you look at the points we're on now, we're probably going to need to win at least the same amount again to stay up.
"The games are running out quickly and if we can get a win on Saturday it could be crucial."
Brunt has scored two goals in 20 Premier League appearances this season.
