Record signing Emile Heskey gave the Latics the lead but it was all square at half-time with Nicolas Anelka hitting the equaliser with his 11th of the season.
Then in a four-minute spell in the second half, Teimourian struck twice to give the Wanderers their first Premiership win over Paul Jewell's side.
Both sides had plenty of motivation for wanting the three points - Bolton chasing a European place for next year and the Latics battling to retain top level status.
Jewell had virtually a full-strength squad available, while Wanderers had both Kevin Nolan and Ivan Campo serving suspensions. Henrik Pedersen was on the bench despite his outburst over Bolton's failure to offer him a new deal.
Wigan were without Dutchmen Arjan de Zeeuw and Denny Landzaat, giving starts to Paul Scharner and Luis Antonio Valencia.
Neither keeper had a save to make in the opening half hour with Wigan enjoying the territorial advantage but failing to hit the target.
Lee McCulloch hit one wide, Josip Skoko had another deflected over the bar and Matt Jackson missed with a close-range header from Ryan Taylor's free-kick.
But Wigan broke the deadlock with an excellent move. Caleb Folan's neat backheel sent Austrian Scharner racing in on goal, his ball into the box appeared to be fumbled by Jussi Jaaselainen and Heskey forced it over the line.
It was his seventh of the season but Wanderers levelled when Jackson's clearance was pumped back in by Gary Speed. John Filan failed to get it away and El-Hadji Diouf supplied the cross and Anelka the finish.
Filan prevented further damage with an excellent save from Diouf.
But Bolton clinched it with that Teimourian double. Diouf set up the first with a great ball - Wigan screaming in vain for offside - and the Iranian got the second with a back-post header from Kevin Davies' cross.