But manager Irvine will take heart from a spirited performance which saw his side bounce back from last week's 5-0 hammering at Reading.
Irvine rang the changes with Leon Clarke, Jermaine Johnson, Tommy Miller and Darren Purse all brought into the starting XI.
It was Clarke who made the most telling contribution as he scored either side of the break.
Irvine said: "It was a great response to obviously what was a very poor performance last week. It was the kind of response that we talked about all week.
"But it's one thing to respond in the right way on the training ground and it's something else to do it on the pitch.
"I'm absolutely delighted with the way the lads went about their jobs from the start of the game.
"I think getting the first goal in this division is vital. We actually had one or two efforts before the goal, even though it came early.
"Leon Clarke has got terrific ability. He is a really good finisher with both feet and has been training really well.
"I was hoping that he would take that onto the pitch and he did do. His first was absolutely terrific from his own point of view and his second was really well made by Jermaine."
Leicester manager Nigel Pearson refused to be too hard on his players with the defeat coming a week after their own emphatic win over Nottingham Forest.
Pearson felt the pitch and Wednesday's tactics contributed to the outcome and said: "We didn't really cope with their style of play. It was a poor game on a poor pitch.
"Wednesday went back to basics and played a high-tempo game and we struggled to deal with that.
"We've played much better this season, although I didn't think we were awful."
The Foxes were forced to make a change in goal midway through the first half after Chris Weale collided with the boot of Marcus Tudgay. Weale was replaced by Conrad Logan, making his first appearance of the season.
Speaking about Weale, Pearson added: "He's got a cut to his nose but had it been an outfield player we would have just taken him off for a couple of minutes, stitched him up and sent him back on.
"Conrad did very well when he came on considering that he hasn't played for a while."