The midfielder slotted past Freddie Woodman with his left foot to break the deadlock after Ali McCann slid in to intercept a Wilfred Ndidi pass across the box but diverted it into his path.

And Dewsbury-Hall sealed only the second home victory in the last 13 league meetings between the two sides by firing into the roof of the net after Woodman kept out Iheanacho's initial effort.

Foxes boss Enzo Maresca gave Conor Coady his league debut in place of the suspended Jannik Vestergaard, but the England defender had a comfortable introduction as Preston were content to soak up pressure and try to hit the home side on the break.

Stephy Mavididi fed a superb ball through to Dewsbury-Hall in the box, but he was foiled by a superb block from Liam Lindsay and that was as close as Leicester came before the break, despite enjoying 75% of the possession.

Ndidi headed over the angle early in the second half before Dewsbury-Hall curled a 25-yarder just the wrong side of the post from Ricardo Pereira's pass.

Preston went close when Duane Holmes fired in a 25-yard shot that Mads Hermansen pushed past the post, but that was their only effort on target.

And after Dewsbury-Hall opened the scoring, he and Ndidi combined to give Iheanacho - sent on to replace Jamie Vardy - an easy finish from six yards.

It left Preston staring at a second successive defeat following Saturday's 4-0 home loss to West Bromwich Albion and any hopes of a fightback were snuffed out when Dewsbury-Hall finished off another fine Leicester move in style.

They are two points clear of Ipswich with another home game against Stoke City on Saturday.

Goalscorer Kiernan Dewsbury-Hall told BBC Radio Leicester:

"We knew what sort of game it was going to be, they're doing well in the league and have a style of play they're pretty good at.

"In the first half they frustrated us a bit, we didn't get many chances with their two banks of four but then at half-time we changed formation.

"Once we got the first goal it opened up a bit more and then we could show more of what we're like.

"It was a really rewarding win and a great game for us to get a bit of daylight between us and third [place]. There's a certain way of playing against that sort of team, you have to be patient."

Preston manager Ryan Lowe:

"It was definitely harsh. I thought we were fantastic for 50-odd minutes until they scored the first goal, which was disappointing on our behalf - we go to ground when we could probably have intercepted it.

"We didn't have much possession but I can't fault the effort. Late on we were out on our feet a little bit, which was expected.

"They have got a player in Dewsbury-Hall who shouldn't be playing at this level. But we didn't fear them, we respected them.

"They are normal human beings but they have got different qualities to most in the Championship."