Leicester boss Marti Cifuentes stuck with the same team held to a goalless draw by Coventry City a week earlier, while West Brom head coach Ryan Mason made three changes following their defeat at leaders Middlesbrough.
On-loan Southampton defender Charlie Taylor started on his debut for the hosts, while Aston Villa loanee Iling-Junior was also brought into the XI for the first time.
And the former Juventus winger wasted no time in marking the occasion in style.
Meeting a deft flicked pass from Aune Heggebo, Iling-Junior outran Boubakary Soumare and skipped around Belgian defender Wout Faes before prodding his finish past Stolarczyk.
The 10th-minute opener had come against the early run of play, with Jordan Ayew dragging a shot just wide inside three minutes.
And after Iling-Junior broke the deadlock, Jordan James had an effort deflected over the bar and Harry Winks hit a volley wide as the Foxes searched for a first-half equaliser.
West Brom continued to soak up pressure after the break and Leicester's quick passing and fluid football created few serious threats.
Vestergaard was presented with the best of them, but he could only send his close-range header into the arms of Griffiths.
The Baggies went on to create numerous chances, with George Campbell lashing a chance into the side netting and Isaac Price hitting a tame effort straight at Stolarczyk before Maja had a volley defected wide.
Substitute Maja then went on to squander his huge chance in the 90th minute, while Toby Collyer curled an effort just wide.
But in added time, a deep cross from Abdul Fatawu was met by substitute De Cordova-Reid, whose flying volley was turned in to his own net by Phillips.