A simply stunning free-kick from Grant McCann earned Peterborough United a vital 1-0 win over Sheffield Wednesday at London Road.
Inside the opening 10 minutes, Posh were desperately close to the breakthrough as Dwight Gayle just couldn't force the ball past Kirkland from close-range after the goalkeeper had parried a Lee Tomlin shot.
On 24 minutes, Bostwick fired over from a set-piece after McCann had been upended 30-yards from goal.
On the stroke of half-time, Gayle was denied by goalkeeper Kirkland after cutting inside on his left-foot.
Sheffield Wednesday made a change at the interval with Kieran Lee replacing Rhys McCabe.
Gayle saw a shot blocked on the line after Mendez-Laing's shot deflected into the striker's path. Gayle then fired over with his left-foot after a hooked through ball from Tomlin.
On 64 minutes, Posh got the breakthrough and it was a stunner, Grant McCANN took his time and curled a superb free-kick via the inside of the post with Kirkland well beaten.
Gayle was inches away from converting a Mendez-Laing cross before Tomlin was denied by Kirkland as Posh, boosted by the goal, went in search of a second.
Joe Newell replaced Mendez-Laing on 82 minutes. Lita was then denied superbly by Olejnik before firing over the rebound.
Kane Ferdinand and Tyrone Barnett were then both introduced into the fray. Five minutes of added time was indicated by the referee Nigel Miller.
Final Score: Posh 1-0 Sheffield Wednesday
Posh: Olejnik, Alcock, Zakuani, Bostwick, Tomlin, McCann (sub Ferdinand 84min), Rowe, Payne , Pritchard (sub Barnett 83min), Gayle, Mendez-Laing (sub Newell 82min). Unused subs: Day, Brisley, Knight-Percival, McDonald.
Sheffield Wednesday: Kirkland, Buxton, Gardner, Maguire, McCabe (sub Lee 46min), Helan (sub Lita 67min), Pugh, Olofinjana, Coke, Howard (sub Madine 73min), Llera. Unused subs: Bywater, Taylor, Semedo, Mattock.