Wednesday brought in Lewis Price with goalkeeper Joe Wildsmith ruled out with a back injury.
Sam Hutchinson also came into midfield, with Atdhe Nuhiu dropping out.
For Leeds. there was no place for striker Chris Wood who failed a fitness test. Sam Byram did not feature with a move to Everton in the offing.
The Owls had a great chance to take the lead after seven minutes. Jack Hunt crossed on the lapover down the right, and Gary Hooper headed over.
Liam Cooper then did well to keep Forestieri out after a break from Barry Bannan.
At the other end, Souleymane Doukara saw his effort deflected into thje hands of a relieved Price.
Wednesday’s goalkeeper kept his side in the contest, twice thwarting United.
Stuart Dallas shrugged off the challenge of Hutchinson to break away, but his shot was palmed away by Price.
When the ball broke to Doukara. he looked certain to score, only for Price to stand tall and block the close-range effort.
Lewis Cook was next to try his luck, but he dragged his effort wide.
It was an end-to-end game and Forestieri tested Silvestri with a 25-yard effort which the Leeds goalkeeper held comfortably.
Wednesday came out in the second half and hit Leeds with a double sucker punch.
First, a short corner found Forestieri, and Hooper bundled the ball over the line.
The pair were involved in the Owls’ second goal soon afterwards.
This time Forestieri tried his luck from long range, and when Silvestri fumbled, Hooper pounced for his sixth goal in as many games.
Steve Evans introduced Alex Mowatt and Mirco Antenucci to try and pep up Leeds, while Lucas Joao replaced Forestieri.
Leeds thought they had scored during the latter substitution. They were allowed to take a free-kick despite Forestieri still walking off the pitch, and Cooper’s effort was ruled out.
From the legitmate free-kick, Wednesday scrambled the ball off the line, Pudil clearing from Wootton.