Sherwood's five-man band
The absence of injured Gabby Abgonlahor forced a change from Tim Sherwood. Instead of two strikers he put out a five man midfield to support Christian Benteke, including Ashley Westwood, who had been rumoured to miss out on the match; never believe what you read in the papers!
Jack Grealish and Charles N'Zogbia were directly supporting Benteke but it was a hugely flexible midfield, as Westwood's presence in front of the defenders allowed Fabian Delph and Tom Cleverley to push forwards. Leandro Bacuna and Kieran Richardson provided width as full-backs. Ron Vlaar and Nathan Baker were the starting centre-backs, while Shay Given retained his place as the Cup goalkeeper.
Liverpool's tactical carousel
Brendan Rodgers used no less than three formations in the match but their initial shape was a 3-4-2-1, with Raheem Sterling as a lone striker supported by Philippe Coutinho and Steven Gerrard, aiming to book a birthday trip to Wembley for the final. Lazar Markovic and Alberto Moreno were the wing-backs, flanking the central midfield pair of Jordan Henderson and Joe Allen. Martin Skrtel returned from suspension in a three-man defence with Emre Can and Dejen Lovren, protecting Simon Mignolet in goal.
First-half: Defences struggle against midfield runners
With both sides playing lone strikers, the attacks revolved around getting midfield players in close support. The Sterling-Coutinho connection was dangerous but Gerrard spent most of the first half watching those two race past him and hovering behind them ineffectually, a worried parent with exuberant children. In the end it was Henderson's run from deep, untracked by the Villa midfield, which cracked open the defence like an egg for Liverpool to take the lead after poor attempts at clearing the ball. However Sterling and Coutinho continued to be the only real threat, with Gerrard way off the pace and Markovic and Moreno timid in their wing play, attempting very few take-ons and poor in their crossing.
In the Claret and Blue offence, Benteke went on the hunt for the vulnerable member of Liverpool's defence immediately, stalking Emre Can down the left. Villa's attack swings towards their Belgian striker like a compass needle to the North Pole, and Grealish and N'Zogbia both joined the pack down that flank at times. Benteke and N'Zogbia almost managed a swift counter-attack in the 15th minute. Brendan Rodgers responded to the danger after 25 minutes by switching to a four man defence with Can at right-back and Moreno dropping into left-back. Markovic pushed ahead to make it a 4-2-3-1.
A combined heatmap of the touches of Benteke, N'Zogbia and Grealish shows their attention on the left side, hoping to isolate Emre Can - image from WhoScored.com.
It was an odd change which did little to stifle the Villans down that side and pushed Can -whose natural position is as a midfielder - even further out of position. As the half progressed, Delph began to conduct the Villa midfield, liberated by Westwood in the anchor role behind him. He almost single-handedly created the goal in the 35th minute, beating both Henderson and Can near the halfway line to drag the Red defence out of position. Bursting down the left wing and exchanging passes with Grealish, he found Benteke in space, who opened his body for the one-touch volley which veered just beyond Mignolet.
At half-time the match was hanging in the balance but Villa were working better as a unit. Delph, Grealish and Benteke were a dangerous spine, benefiting from Westwood and Cleverley's effort in winning and rotating the ball. For Liverpool, Sterling and Coutinho were lively but lacked support from Gerrard, the flanks, or further back with the exception of Henderson's run for the goal.
Second-half: Rodgers' change backfires
Brendan Rodgers clearly agreed that there wasn't enough attacking support and Gerrard wasn't working as an attacking midfielder. He took off Markovic for Mario Balotelli to lead the line, with Sterling and Coutinho on either side and moved Gerrard to the base of the midfield in a 4-3-3.
These were questionable changes. Balotelli's spell at Liverpool has been unimpressive precisely because of his lack of success as a lone striker during Daniel Sturridge's absence, and Gerrard's struggles during his attempted reinvention as a deep midfielder are well-known - his passing range is brilliant but his energy and defensive intelligence are suspect. What was he going to contribute in the position for the second-half?
The change did rather more for Villa than for Liverpool. Suddenly there was space in front of the Liverpool back four, especially for Grealish, and the Red midfielders did nothing to close off the passing lanes. In the 54th minute Delph broke past that midfield to find Benteke who back-heeled it to Grealish in space. With time to compose himself, the teenager played a reverse pass into Delph who had continued to the box. He flicked it inside the retreating centre-backs, planted his left foot and wrenched his body round to squeeze a shot past Mignolet. Villa were set to go to Wembley and Rodgers' change had backfired badly in defence.
It didn't help much in the search for an equalizer either. Balotelli worked hard and fashioned a few half-chances but couldn't seem to connect with Sterling and Coutinho who were now further away from each other. Coutinho in particular began to drop strangely deep and faded out of the match. Villa were threatening on the counter and with a better weight of pass could have increased their lead. The 77th minute arrival of Glen Johnson, taking off Allen and pushing Can up to the midfield invigorated Liverpool slightly, with a header cleared off the line and Balotelli wrongly ruled offside before putting the ball in the net. But a heroic performance from Ron Vlaar in the last thirty minutes, providing aerial presence and a quick tackle on the ground, was enough for the Lions.
A strange match tactically in which Sherwood's five man midfield worked from the first minute while Rodgers twisted and contorted his Liverpool side without improvement. In particular they never solved how to deal with the combination of Delph, Grealish and Benteke, nor how to get their own attack going in numbers.
Jores Okore on for Nathan Baker (25m) - Injury forced sub. Gutting for Baker and briefly gutting for Villa when Okore messed up in the first goal. Improved but still struggled with Balotelli late on and lacks Baker's aerial ability.
Scott Sinclair on for Charles N'Zogbia (74m) - Tactical but a like-for-like substitution, to concentrate on counter-attacking pace. N'Zogbia had a mixed day, with good movement but poor touch. Sinclair had very little opportunity to do anything.
Joe Cole on for Jack Grealish (82m) - I'm now resigned to the late Joe Cole show. Perhaps it's a good idea to have a canny time-waster, but didn't we all want to see a Grealish goal to finish it off?
Conclusions - A huge step for Sherwood and Villa
First of all I have to admit I was wrong. I assumed Sherwood was too attached to having a partner for Benteke to experiment with a five-man midfield and I automatically believed newspaper rumours that he had dropped Westwood. Instead he played a five man midfield with Westwood as the anchor for 90 minutes and it worked beautifully. Neither he nor the side panicked when we went behind and they played well for the whole game.
This feels like a huge step with a team with a long injury list. Wins over Tottenham and Liverpool back to back should leave this team feeling confident against any opponent. Benteke, Grealish and Delph are lethal together and can raise the level of their teammates. If we can survive the centre-back crisis, we're in a great position. And Tactics Tim, he of the gilet, Tim Sherwood is leading us to an FA Cup Final.