The 33-year-old Frenchman, snapped up on a free transfer from Newcastle, broke the deadlock with a scruffy goal in the 55th minute.
Boro battled back but their luck was out with Stewart Downing firing just wide and then seeing another ferocious strike hit the post.
Wigan had bossed the first half but it was all square at the break with keeper Mark Schwarzer the Boro hero.
The Latics had made just one change to the starting line-up with Sibierski taking over from Caleb Folan alongside Emile Heskey up front.
Boro were unchanged and prospective £6.8million signing Mido was among the spectators in the directors' box.
Wigan got off to a confident start and went agonisingly close to taking the lead after 25 minutes.
Boro conceded a free-kick for a foul on skipper Mario Melchiot and Jason Koumas beat the wall forcing Schwarzer to tip it around his left post.
Earlier the Latics had carved out other openings with Welsh star Koumas making a big impression on his home debut.
The first came after just four minutes when Luis Antonio Valencia provided the cross, Denny Landzaat stepped neatly over it, and Sibierski seized the chance to shoot but put it over the bar.
Boro stemmed the tide briefly with Turkish star Sanli Tuncay just missing with a left footer, and right-back Melchiot came up with an important block to deny Downing a chance to strike.
But Schwarzer was busy keeping out tricky shots from both Koumas and Sibierski as Wigan turned the screw.
The goal came when Valencia hammered in a fierce low shot from the edge of the box, the keeper could not hold onto it and Sibierski scrambled it in from a couple of feet.
After the two close shaves from Downing, Wigan had chances to put it beyond all doubt but both Paul Scharner and Heskey hammered shots wide.