Wednesday twice took the lead in a pulsating first half through goals from Atdhe Nuhiu and Sam Hutchinson, who was later sent off.
Bournemouth hit back thanks to efforts from Marc Pugh and the in-form Yann Kermorgant either side of the interval - only for sub Leon Best and Chris Maguire to strike late on.
Chris Kirkland was called into action for the first time in the 12th minute and needed all his agility to somehow turn the ball past a post and stop Lewis Grabban's shot from an acute angle finding the corner of the net.
Bournemouth fans among a sell-out 10,864 crowd fell silent four minutes later when Nuhiu took advantage of more sloppy defending from the home side to give Wednesday the lead.
Steve Cook mishit an attempted pass straight to the feet of the Nuhiu and the giant Austrian striker controlled the ball neatly before rifling past a helpless Lee Camp from the edge of the penalty area.
Bournemouth drew level 14 minutes before half-time when the lively Grabban sprinted past three defenders before crossing for Pugh to head beyond Kirkland at close range.
But the Cherries' joy lasted just three minutes until Chelsea loanee Hutchinson headed Wednesday back in front with his first goal for the club after a long throw from Michail Antonio had caused confusion in the box.
Grabban was denied an immediate equaliser straight from the restart as his effort from 12 yards was beaten away by Kirkland.
Kirkland had the final word of an entertaining first half, flinging himself down to his right to turn Andrew Surman's low shot wide for a corner.
But there was nothing Kirkland could do to prevent Kermorgant heading Bournemouth back on terms for a second time on 58 minutes from Ian Harte's corner.
Wednesday were forced to see out the final 27 minutes a man light after goal hero Hutchinson was shown a second yellow card for a late lunge on Kermorgant.
Kermorgant was denied a second goal by another brilliant intervention from Kirkland as the Frenchman's 20-yard free-kick was tipped onto the crossbar.
Best struck the killer blow in the 87th minute, tucking home the rebound after Antonio hit the crossbar at the end of a fine solo run.
Maguire made it 4-2 in stoppage time, tapping in Best's centre from six yards as Bournemouth were caught pushing for an equaliser.