After the home side had missed a penalty, Mauro Formica opened the scoring in the 34th minute with a powerful header before David Dunn's free-kick and substitute Nick Blackman's spot-kick wrapped up the win in the second half.
Kitchee were presented with an early opportunity thanks to hesitancy in the Blackburn defence but Roberto Losada shot straight at keeper Mark Bunn.
Brett Emerton then saw an effort blocked on the line and Morten Gamst Pedersen curled a free-kick just wide of the post.
The hosts then wasted a golden opportunity to take the lead in the 22nd minute when Martin Olsson felled a Kitchee player in the box but skipper Ubay Luzardo, who scored an own goal in the 4-0 defeat by Chelsea on Wednesday, blazed the penalty over the bar.
It was to prove costly as 11 minutes before half-time, Emerton's measured cross was headed home from close range by Formica.
Olsson's long-range effort was then pushed away by keeper Wang Zhenpeng as the half drew to a close.
Pedersen's header was kept out by Wang 10 minutes into the second period and Chan Man Fai rifled inches wide at the other end.
Blackburn's second came in the 69th minute when Dunn lifted a sublime free-kick into the back of the net after Ruben Rochina's mazy run was halted unfairly near the edge of the box.
Luzardo's misery was further deepened when he bundled Blackman over in the box with seven minutes to go and the striker picked himself up to despatch the penalty into the top corner and seal what ultimately proved a comfortable victory.