Liverpool, so vocal in their quest to win the tournament this season, were clearly unsettled by the early and worrying loss of key defender Martin Skrtel but the unconvincing display that followed from the Premier League side was as unforgivable as it was unexpected.
Manager Brendan Rodgers remained defiantly upbeat, despite evidence to the contrary, and insisted his side had been denied a clear first half penalty after a clumsy challenge by Matt Kilgallon on Adam Lallana.
“I am not overly disappointed,” he said. “Of course we wanted to get through. But we kept a clean sheet against a dangerous team, especially from set-pieces and long balls into the box. We are still there to reach the semi-finals.
“I definitely thought we should have had one penalty. It was a great move and he got his body between man and ball and as he went to shoot he was knocked over. I thought that was a clear penalty.”
The sickening injury suffered by Skrtel, inside the opening two minutes after his head struck the ground awkwardly following an aerial challenge with Rudy Gestede, clearly impacted upon Liverpool’s defensive game-plan and allowed the Championship side to enjoy long periods of threat.
Had the uncompromising Skrtel been present as one of the Rodgers’ three defenders, it might have made for a more comfortable afternoon for the home side. As it was, Dejan Lovren and substitute Kolo Toure struggled to cope with Gestede’s height and physical presence and Rovers thrived.
Gestede headed just wide as he outjumped Simon Mignolet in the early exchanges and, although Rovers survived that strong penalty claim on Lallana in their area, Blackburn grew in stature.
Toure was required to make a superb tackle on Ben Marshall at the end of a flowing Blackburn move, the unconvincing Glen Johnson chested the ball into the side-netting and within inches of his own goal with Gestede poised, and Marshall planted a long throw-in onto the head of Gestede for Mignolet to save.
Gestede started, and almost finished, another enterprising move, eventually re-appearing on the end of Marshall’s far post cross and producing a volley which was blocked by Raheem Sterling with television replays suggesting he may have inadvertently handled in the process.
Poor positional play by Toure allowed Blackburn to link together dangerously yet again, Gestede this time dummying Tom Cairney’s pass for the fast-arriving Craig Conway to rush a shot high and wide.
Finally, Liverpool responded although Toure’s close-range finish from a set-piece was wasted as his ‘goal’ was ruled out for offside and, in the eight minutes of first half injury-time for Skrtel’s injury, the Blackburn goalkeeper Simon Eastwood was finally called into action, first saving a deflected Lazar Markovic shot and then, more impressively, punching away the first shot on goal to come from Daniel Sturridge.
It had been a frustrating half for Sturridge, and his team, in their attempts to break down a disciplined Rovers defence and the opening of the second offered little immediate improvement.
Indeed, it took a magnificent save from Mignolet to keep his team in the tie as the Liverpool goalkeeper leaped to tip over a powerful Alex Baptiste header as the Blackburn defender rose to meet a Conway corner.
Sterling had a shot blocked from a threatening position and Toure again looked dangerous at a set-piece, heading against the foot of a post, only for the defender to once more be flagged for offside. By the time the latter occurred Rodgers had thrown on Mario Balotelli in an attempt to penetrate the massed, organised Blackburn defensive ranks.
Toure, yet again, briefly threatened to do so as he met a Philippe Coutinho corner with a scrambled shot that was deflected behind and the increased tempo of the second half, plus their switch to two forwards, was finally allowing Liverpool to establish dominance.
Balotelli added to the mounting disquiet at Anfield with a shot from 35 yards which cleared the bar by almost the same distance although the Italian almost redeemed himself with a clever pass for Sturridge which the England forward shot wide on 73 minutes. The Italian made room for himself after 81 minutes but steered an 18-yard shot directly at Eastwood before he was forced into another save, this time from a low Jordan Henderson shot but it was a rare moment of concern for the Blackburn goalkeeper.
Blackburn boss Gary Bowyer, whose side is still emerging from a tempestuous fall from the heights of the Premier League, was delighted by the performance of his team and the prospect of a replay on April 7 or 8.
“Our players were pleasantly delighted to see so much grass on the pitch at Anfield,” joked Bowyer. “At Ewood it is not like that. I know Brendan was complaining about the pitch here. Wait until he sees Ewood. It makes this look like Wembley.”
LIVERPOOL (3-2-4-1): Mignolet 6; Johnson 5, Skrtel (Toure 10, 5), Lovren 5; Can 7, Henderson 7; Markovic 6 (Balotelli 58, 5), Lallana 8, Coutinho 6, Sterling 7; Sturridge 7.
BLACKBURN (4-4-1-1): Eastwood 7; Henley 7, Baptiste 8, Kilgallon 8, Olsson 7; Conway 9, Williamson 7, Evans 7, Marshall 7 (Taylor 68, 7); Cairney 7; Gestede 8.
Referee: A Marriner 7.