Following a goalless first half, the Welsh side took control of the game after the break to record a 4-0 victory against the league's bottom team.
De Guzman scored his team's second goal of the afternoon with a spectacular strike and admitted that at half time the players knew they needed to improve their performance.
"We're very happy with the win," he told the club's official website. "The first half was a bit sloppy with our passing, and we knew we needed to raise the tempo.
"He (manager Michael Laudrup) just pointed out the small details, such as our movement off the ball. These are things we practice in training and he reminded us of that. When you go two goals up you need to stay patient and not give anything away.
"We knew they would want to try and get one back, but we continued to move the ball around well. We managed to do that in the second half and got our rewards."
Swansea moved up to 11th in the Premier League table after today's win.