Blackburn, who learned during the evening that Manchester United have given them permission them to talk to Brian Kidd about their managerial vacancy, were the more enterprising side until Lennon collected his first goal of the season midway through the second half.
All that was missing in Blackburn's display apart from the lapse in concentration which allowed Lennon a free header, was a modicum of good fortune and more ruthlessness in front of goal. Kevin Davies, the pounds 7.25m signing from Southampton, struck the crossbar with the best shot of the game yet also passed up two simpler opportunities to score his first goal since January.
Martin O'Neill, the Leicester manager, acknowledged that the visitors had belied their lowly status. "We didn't play well. It wasn't a good game and we won," he said by way of a terse but accurate summary. "We obviously had a few problems with injury, as did Blackburn, so it really pleases me that we're in the semi-finals."
Leicester may, in theory, have drawn the easiest of the three other teams left in the competition. However, they have now knocked out three top- flight clubs. Charlton and Leeds were both left wondering how they had lost; Blackburn opened as if determined to avoid the same fate.
Despite the absence of seven first-choice players, they carried the game to Leicester. The better chances inevitably fell to the hapless Davies. Set up by David Dunn near the penalty spot, he betrayed a lack of confidence by effectively passing the ball straight to Kasey Keller.
Minutes later, he flicked a harder chance over the top from a similar position. Then, with Keller beaten, he quivered the woodwork with an angled drive from 25 yards. Davies' shoulders drooped like a man who is beginning to feel he may never find the net again.
The ebullient Lennon has no such problems. Within a minute of O'Neill's decision to push Matt Elliott up from the back into the target-man role performed by Emile Heskey until he limped off with an ankle injury, Garry Parker initiated the move which led to the breakthrough.
Robbie Savage continued it, swinging his centre in from the right touchline. Blackburn's defenders, possible distracted by the physical presence of Elliott, could only watch as Filbert Street's second favourite Northern Irishman lit up a bitterly cold evening.
Leicester City (3-5-2): Keller; Sinclair, Elliott, Walsh; Savage, Lennon, Ullathorne, Parker, Guppy; Fenton (Taggart, 65) Heskey (Wilson, 57). Substitutes not used: Zagorakis, Campbell, Arphexad (gk).
Blackburn Rovers (4-4-2): Filan; Kenna, Henchoz, Dailly, Davidson; Johnson, Dunn, Marcolin, Duff; Davies, Gallacher. Substitutes not used: Croft, Perez, Thomas, Broomes, Fettis (gk).
Referee: A Wilkie (Chester-le-Street).Reuse content