Matt McClure made it four goals in a week as he followed up his midweek brace against Rotherham with another two strikes against the Brewers while Joel Grant rolled in a penalty after Burton captain Zander Diamond was sent off.
After Saturday's League Two triumph at Adams Park, Ainsworth said: "I think that we don't have to fear anyone in this league after that result and I've believed that since I took over.
"It's coming to fruition now - I knew we weren't going to win every game but I think today has proved that we'll win more than we'll lose.
"The first half was a real battle against the elements and 11 men and at half-time the players were tired as though they had played 90 minutes.
"Matty is an out-and-out goalscorer because he is one of those strikers that plays as high as he can and is almost offside half the time. I believe in Matty, I believe he can score and that he can be our double-figure man this season if he can continue the way he is going."