The trouble with this much-of-a-muchness Championship is that when you think you have got it cracked, you stumble. And when reinforcements appear essential, along comes a victory as conclusive as this that may beg a rethink.
Sunderland, more adept than most at taking three steps forward and two back, have ushered in the transfer window with a performance rivalling their best under Roy Keane.
It took them almost three hours of new year weekend football to score, but the late goals by Tobias Hysen and David Connolly were richly deserved and should have been accompanied by more. "I thought we would get there in the end," said Keane of a one-sided contest. "We had to be patient and showed great perseverance and desire. We're heading in the right direction."
Now Wearside holds its breath. "There may be one or two coming in this week and one or two going out," he added.
While Leicester City are crying out for a resolution to the Milan City Mandaric saga and the recruitment of much-needed quality, Sunderland made light of their injuries to impress everywhere except in front of goal, where goalkeeper Paul Henderson heroically frustrated them for 79 minutes.
One save from Connolly was of the highest order, the former Leicester striker looking a scorer all over with a left-foot shot on the turn from Chris Brown's centre that the Australian somehow got down to and pushed wide, earning him a hug from two of his defenders.
Not that it did more than delay the inevitable. When a header by the substitute Daryl Murphy crashed against a bar from Dean Whitehead's cross, Hysen nodded in the rebound and the floodgates were opened.
Within four minutes, Connolly had an effort disallowed for offside and tucked in the second when Henderson saved well from the clean-through Murphy.
The fact that 89 minutes had passed before Leicester managed their first on-target of the game said everything.
"No complaints whatsoever," said the home manager, Rob Kelly. "We were well beaten by the better side and have had two poor performances over the weekend."
The worst of Sunderland's many misses came when Hysen shot over from eight yards from Brown's pull-back while Stanislav Varga was denied by an instinctive tip-over and Murphy was given offside as he side-footed in, with Liam Miller ready to score legitimately almost at his side.
Leicester City (4-4-2): Henderson; Stearman, McCarthy, Kisnorbo, Kenton; Hughes, Wesolowski (Cadamarteri, 62), Williams, Porter; Fryatt, O'Grady (Hume, 62). Substitutes not used: Logan (gk), Tiatto, Maybury
Sunderland (4-4-2): Ward; Whitehead, Varga, Nyatanga, Wallace; Elliott, Miller, Yorke (Leadbetter, 59), Hysen (Hartley, 84), Connolly, Brown (Murphy, 59). Substitutes not used: Welsh, Fulop (gk)
Referee: S Mathieson (Cheshire).