The Bolton keeper showed his quality especially in the first half to prevent the Latics from storming into a healthy lead as they looked to bounce back after three straight Premier League defeats.
His first contribution came after just two minutes when Mido set up a chance for Hugo Rodallega with a neat back-heel.
The £4.5million Colombian striker - hunting his first Wigan goal - hit his shot well, but the keeper reacted superbly to get a hand to it and steer it against his left post.
The Finland star followed that by diving to his left to turn away Charles N'Zogbia's effort and then blocked from Rodallega who cracked one in from point-blank range.
Wanderers found their luck was out too when Wigan failed to clear a Gavin McCann free-kick, and Gary Cahill's shot was deflected onto the crossbar.
The Latics were looking the more likely to break the deadlock but Matthew Taylor got in a vital block on Mario Melchiot as the Wigan skipper was about to shoot.
Antonio Valencia had Bolton on the back foot with a terrific break but again the busy Rodallega failed to hit the target.
The Trotters almost cashed in on a slip by Maynor Figueroa but Johan Elmander - once a Wigan target - hammered into the side-netting.
But once again Jaaskelainen came to the rescue with another stunning save when Mido pounced on a mistake by Fabrice Muamba to have a crack.
Bolton did get the ball in the net in first-half stoppage time but an offside flag cut short Taylor's celebrations.
Chris Kirkland was forced into action to keep one out from McCann at the back post, Mido wasted a clear chance firing wide after Rodallega had set him up, and Elmander saw a goal-bound effort deflected for a corner.
Wanderers were hunting a winner but Latics survived when a clearance attempt from Erik Edman hit Titus Bramble gifting Kevin Davies a shot at goal. However, he hit it well clear of the bar.
And, in the last minute, Wigan fans held their breath when Davies went down under the challenge from Emmerson Boyce in the box but ref Mike Jones ruled it was legitimate.