HEADED goals from Greg Halford and Elliott Ward helped Nottingham Forest overcome battling Peterborough and secure Alex McLeish's first win as Reds boss.
Defenders Halford and Ward both struck from corners, either side of an equaliser from Scott Wootton.
Peterborough had not claimed a single point after going behind in matches this season – but looked good for a point until Ward rose to head home at the far post in the 83rd minute.
It was a welcome moment for McLeish, who had demanded his side bounce back with an improved performance following their humbling FA Cup exit at the hands of Oldham last weekend.
Karl Darlow, starting a league game for the first time for Forest - after Lee Camp had been told he is free to find another club - was given a warm reception, by the City Ground fans.
And he had to be alert to race out of his box and clear the danger when Davide Petrucci chased a through ball in the first two minutes.
Petrucci, one of the Manchester United starlets on loan at Peterborough, produced the game's first real moment of menace. The striker's outstanding turn on the edge of the box helped him to elude Dan Harding, but Elliott Ward was across quickly to make an important block on his driven shot.
A driving, probing run from Harding almost carved out an opportunity at the other end, but Radi Majewski's attempt to slide him in down the centre was narrowly over hit.
Darlow had to make his first save of the game in the 12th minute and it was a good one as Dwight Gayle bent a precise shot towards the far post, which the keeper held well, albeit at the second attempt.
Majewski missed the best opportunity of the opening exchanges, following a flowing attack down the Forest left that culminated in a good cross from Harding, with the Pole lifting a shot over the bar from 12 yards, with the goal at his mercy.
When Majewski won a corner with some determined play of his own down the left, it led to the opening goal. Lansbury whipped the ball towards the far post where Halford rose to send a looping header towards goal.
Kane Ferdinand made a brave attempt to clear the ball off the line, but referee Eddie Ilderton, with the aid of his assistant on the near side, ruled that it had crossed.
Petrucci tested Darlow's reactions almost immediately as Peterborough pushed for an equaliser, but the keeper looked to have his shot covered as it fizzed into the side netting.
A combination between Cohen and Sharp carved out a half-chance for the striker on the edge of the box, but he flashed his shot across goal and wide.
Sharp was rather closer to a goal following some impressive skills from Simon Cox, who left the Posh defence for dead with a neat turn before crossing to the far post where Sharp saw his header brilliantly saved by Bobby Olejnik.
Former Forest loan signing George Boyd was denied by Darlow, with the keeper producing his best stop yet, sliding in bravely at the midfielder's feet and holding on to his shot well, from close range.
The second half began with Forest having to hold out under a short spell of pressure. But when Gonzalo Jara lofted an outstanding pass down the centre of the pitch, it looked as though Cox was through on goal, before Olejnik raced out to narrowly beat him to the ball.
Ward, pushing forward from the back to join the attack, then found himself with a free header when Cohen delivered into the box, but sent his effort straight at the keeper.
Lansbury also came close to adding a second for Forest as he bent a shot from just outside the box that had Olejnik scrambling across goal nervously.
It proved to be a telling moment as, on the hour mark, Peterborough drew level. A corner from the Forest left was not cleared at the far post and, when the ball dropped to Wootton, he lashed the ball into the back of the net.
It was a moment the Manchester United man clearly enjoyed, having played for both clubs last season – and he celebrated joyously in front of the travelling fans.
Cox came within a whisker of putting Forest ahead again when he and Sharp combined, with Sharp crossing into the centre where Cox just failed to make contact with his head.
Peterborough's other former Forest man almost found the net then, with Boyd flashing a shot across goal and narrowly wide, with Darlow at full-stretch, diving to his left, to cover.
But Forest, driven by a lively performance from Majewski, were also not without threat. Gillett had a long range effort deflected for a corner, with Olejnik having to be dominant in his box as the home side delivered balls into the danger zone.
When Cox turned his marker and charged into space down the left, Forest should have taken the lead for a second time, but Majewski was uncharacteristically wild with his shot, after he had been picked out with a clever cut back.
Forest were creating opportunities, with a Cohen cross then narrowly eluding Sharp in the centre, before finding it's way through to Harding on the edge of the box, where the defender controlled brilliantly, before firing a shot high into the stand.
McLeish made a change with ten minutes to play, bringing on Jonathan Greening for the tiring Lansbury.
But it was to be another goal from a defender that edged Forest in front again, with Ward powering home a header at the far post after Majewski had curled a corner enticingly into the danger zone.
While Peterborough threw on a few attackers in the search for another goal, Forest introduced Guy Moussi for Majewski – and were able to hold out until the final whistle to secure a hard fought, but deserved three points.
Forest: Darlow, Jara, Halford, Ward, Harding, Cohen, Gillett, Majewski (Moussi 88), Lansbury (Greening 80), Cox, Sharp. Subs: Evtimov, McGugan, Moloney, Derbyshire, Blake.
Peterborough: Olejnik, Brisley (Mendez-Laing 88), Bostwick, Boyd, Rowe, Newell (McCann 86), Ferdinand (Gordon-Hutton 57), Little, Petrucci, Wootton, Gayle. Subs: Alcock, Day, Knight-Percival, Richens.
Referee: Eddie Ilderton, Tyne and Weir
Attendance: 22,777 (1,636 away)