The Latics sit 19th having conceded 24 goals in 13 matches and the Dutchman feels that the past two weeks has seen a slight enhancement in the performance of the defence.
But he knows Arsenal's visit tomorrow will be tricky and has urged the team to step up, especially down back.
"It's important we remain tight at the back, because that will be important with some big games coming up," he told the Wigan Evening Post.
"The defence was solid throughout the Sunderland game, which helped us to get the win. And to be honest it was the same against Blackburn, after we conceded that first goal.
"The other goals we conceded were to a penalty and a corner, we didn't give much else away.
"At home we don't fear anyone, and we can give Arsenal a real game if we keep up our performance levels."