The Serb tycoon, who isn't expected to complete his takeover until mid-December, was at the Walkers Stadium for the first time but was keeping what he thought of City's performance to himself.
The game had been drifting towards half-time when, in the 43rd minute, it burst into life when the Owls were awarded a hotly contested penalty.
Josh Low and Wayne Andrews challenged for a half-cleared corner and referee Rob Styles stunned the home side by ruling that the City player's raised boot constituted foul play.
In the protests that followed Leicester's assistant manager Mick Stowell was banished from the dugout, Conrad Logan and Paddy McCarthy were shown yellow before Chris Brunt calmly dispatched the penalty low to the keeper's right.
And four minutes after the restart McCarthy's misery was complete when he was sent off for his second yellow after a foul on Glenn Whelan.
There was worse to follow for the home fans on 53 minutes when a loose ball which had rebounded off the referee fell invitingly into the path of Brunt who gratefully drove home from 20 yards.
The Foxes rallied and were thrown a lifeline on 57 minutes when Iain Hume's speculative long-range drive took a huge deflection off a Wednesday defender on its way into the net.
Then, in the space of two minutes, veteran keeper Mark Crossley kept the Owls' lead intact when he denied Elvis Hammond and Levi Porter with tremendous stops.
After that Leicester fell apart and on 70 minutes Whelan scored with a 30-yard thunderbolt that went in off the bar before, a minute later, Marcus Tudgay curled home from 18 yards out.
Six minutes from the end Patrick Kisnorbo headed against the bar but there was no way back for City.