Steve Chettle thumped home the penalty. Five minutes later Dougie Freedman claimed his second of the match and three minutes from the end Wright earned deserved reward as he slipped the ball past the stand-in goalkeeper, Carl Emberson.
The Walsall manager, Ray Graydon, said it was the first time this season his promoted team had been second best. "I can't wait to get out of here," he admitted. "It isn't a pleasant sight to watch your side well beaten. We were nowhere near them."
Honest and true. Walsall had a wonderful boost of a goal after only four minutes, and they defended this lead doggedly until almost half-time through the bulk of Tony Barras and the goalkeeping heroics of Walker. But after the interval Petrachi tormented the left side of Walsall's defence and their cave-in always seemed on the cards.
However, Forest were so long turning their domination into goals that Platt, who had named himself as one of the substitutes because of an injury crisis among his midfielders, was warming up after only an hour. His arrival with five minutes left was more in the nature of a celebratory trot than anything else since, in his opinion, all 11 Forest men were heroes.
They looked anything but heroic after that early setback. By then Wright had already gone close to scoring, chipping Walker with a delightful effort which landed on the roof of the net. Walsall raced away from the goal- kick, Darren Wrack crossed from the right and Mark Robins, from a very long way out indeed, struck a perfectly timed header high to Dave Beasant's leap to his left.
Petrachi, Freedman, John Burns and Wright all came close to the equaliser, but there were only three minutes to the safety of the dressing-room when Walsall capitulated. The credit goes to Petrachi, who forced his way into the area and drew Walker before his shot was blocked. The rebound fell kindly for Matthieu Louis-Jean, who crossed for Freedman to head in.
The timing of that goal was the boost Forest needed to take the match to Walsall and keep them penned in their defensive zone. Walker was constantly in action as Forest clipped both uprights and Wright floated another chip on to the bar.
Walsall could not contain Petrachi and it was his darting run into the penalty area which led to the second Forest goal. Put through by Nigel Quashie with Walsall looking for the offside flag, the Italian rounded Walker but was pulled down. The referee Kevin Lynch's red card was a formality and, once Emberson had replaced him in goal just in time to pick Chettle's penalty out of the net, Walsall were goners.
Forest's third was a beauty. Alan Rogers and Petrachi worked a short corner on the right, Petrachi transferred the ball to his left foot and swung over a precise cross to the far post, where Freedman squeezed his header between the upright and a hesitant goalkeeper.
Emberson managed to stop one when he thrust Quashie's storming drive over his head, then hurriedly rescued the ball as it bounced towards goal. But he was nowhere when Wright struck the woodwork again.
With two minutes left, Wright collected from Riccardo Scimeca and got in a shot which Emberson parried, but could not keep out.
Wright is only on loan for another couple of weeks from West Ham and Platt is understandably keen to keep him, since he is forming a potent spearhead with Freedman. "In the space of a week they are getting a very good understanding together," he said. With Harry Redknapp's indulgence, they may go on to greater things.