... and so cruised through to the last four of the FA Cup for the first time since they won the competition five years ago.
After scoring five times in ten matches, Liverpool took their goals tally to 15 in a week. Peter Crouch took his personal tally into double figures, but Benítez combined compassion with praise after the biggest win of his spell at Anfield. The heaviest defeat in Steve Bruce's five-year reign at St Andrew's might make the Birmingham manager believe that he reached rock bottom, but the fixture list may give him reason to reconsider. Next up for the relegation-threatened team are the only two teams above Liverpool in the Barclays Premiership. Bruce, afforded a police escort from the dugout, will just be hoping he makes it as far as Old Trafford this Sunday.
However bad Birmingham were, Liverpool were imperious. Emile Heskey, the former Liverpool striker, and Nicky Butt, on loan from Newcastle United, were the latest to join St Andrew's casualty ward.
Birmingham had barely touched the ball before finding themselves cut two goals adrift. After 55 seconds, Sami Hyypia was given the freedom of the Tilton Road End to head in from six yards after Mohamed Sissoko nodded on Steven Gerrard's free kick, awarded for David Dunn's rash tackle on Xabi Alonso. Then Sissoko prodded the ball out wide and Gerrard crossed for Crouch to amble in behind Kenny Cunningham and head straight at Maik Taylor. The ball bobbled off the Birmingham goalkeeper and over the line.
Sissoko, playing barely a month after it was feared he would lose the sight in his right eye, could not have asked for a more comfortable match in which to return. The Mali midfield player, wearing protective goggles, had time to wander over to the touchline and change his glasses during the first half when the first pair filled with condensation.
Soon it was the 4,000 travelling Liverpool supporters coming over all misty-eyed. Seven minutes before the interval Crouch side-footed assuredly past Taylor after Luis García's exquisitely delicate touch, after Gerrard had played through Crouch's header from Steve Finnan's throw-in. Liverpool knew they were through to the semi-finals, even if some half-time wag warned them to remember Istanbul. The European Cup final may have produced a footballing miracle but Birmingham, as last night proved, are not Liverpool.
Just before the break, a Birmingham fan managed to get on to the pitch and made a bee-line for Bruce. Stewards cut him off in time and escorted him down the tunnel. A second individual pitch invasion midway through the second half epitomised the mood as the majority refused to turn on their manager.
The match took on a surreal atmosphere, the home supporters refusing to get on the backs of their own team while the Liverpool fans enjoyed their own sing-song.
After Alonso's delicious lob was tipped over by Taylor, Fernando Morientes scored the fourth goal of the night. García dummied Finnan's pass for Gerrard to step inside Marcos Painter and roll the ball across for the former Real Madrid striker to tap home, three minutes after his arrival. With 20 minutes remaining, John Arne Riise smashed home the fifth into the top corner.
Olivier Tebily turned Harry Kewell's cross in past his own goalkeeper before Taylor allowed Djibril Cissé's drive to go through him two minutes from time. “We have been criticised a bit lately for not scoring enough goals but we put that right tonight,” Gerrard said. Not a bad time to be asking the neighbours round on a Saturday lunchtime, then, as Everton prepare to come to Anfield.