With both sides embroiled in the fight to stay up this season, the Dutch midfielder knows that claiming three points would go a long way to preserving Swansea's top-flight status.
The Welsh side have not won in three league matches, but things are much worse for West Brom, who are yet to taste victory under head coach Pepe Mel.
And De Guzman is confident that Swansea will have too much for their relegation rivals when they meet at the Liberty Stadium on Saturday.
"It is a massive game and we'll be looking for three points because they're well needed," the 26-year-old told the South Wales Evening Post.
"I don't think it's important to look at other teams, it's very important to look at ourselves.
"With the way we've been playing in the last couple of weeks, although the results haven't come in, we shouldn't have too many problems.
"I think it will help a lot to have a week between games with nothing in the middle. We can only focus on the Premier League and staying safe.
"With the way we've been playing, we've shown a lot of heart and a lot of desire."
De Guzman also praised the form of Wilfried Bony and the Ivorian's influence on the team.
"Bony's a player who can hold the ball up front, so that gives me more confidence to go forwards," he added.
"When he has the ball I know he's creative up front, so if you're in space he can give you that ball.
"I have confidence in him. If you're not sure someone will keep hold the ball you're hanging back a little, but with Bony it's not like that."
