After all, they had recruited a three-time Champions League winner who had been a prolific marksman for Real Madrid to the tune of 72 goals in 112 La Liga starts.
Yet, from very early on into his spell at Anfield, it became apparent that the Spanish international had left his clinical touch at the arrivals gate of Liverpool's John Lennon Airport.
When he returned to his native Spain with Valencia for £3m in the summer of 2006, the frontman had scored just 12 goals in 61 appearances for the Reds.
© Getty Images
That's not to say that there wasn't the odd bright moment to Morientes's fleeting Premier League tenure, such as when Middlesbrough visited Anfield nine years ago today.
The hosts had won their last six league encounters, despite the fact that Morientes had struggled for form for most of the campaign. Boro, though, would be on the receiving end as the centre-forward briefly rediscovered his range.
Following a goalless first half, Liverpool boss Rafael Benitez replaced Peter Crouch with Luis Garcia and the Spaniard went on to make an almost instant impact in the 72nd minute. It was his low cross that found his compatriot Morientes, who having taken one touch, then found the bottom corner of Mark Schwarzer's net.
That was followed by a second Morientes goal just five minutes later as the three points were secured. Boro defender Franck Queudrue misplaced his headed clearance and Morientes pounced, before lobbing his effort over a helpless Schwarzer.
© Getty Images
Speaking after the final whistle, Benitez was full of praise for his two-goal striker, saying: "Fernando Morientes has been playing well but as a striker one of the most important things to score goals and he did that in this match.
"It is his best performance for Liverpool and he finished both his goals very well. The whole team performed well and it was a pleasing home display."
LIVERPOOL: Reina; Finnan, Hyypia, Carragher, Riise; Gerrard, Alonso, Sissoko, Kewell; Morientes (Josemi), Crouch (Garcia)
MIDDLESBROUGH: Schwarzer; Bates, Southgate, Riggott, Queudrue; Morrison (Hasselbaink), Doriva, Boateng, Rochemback; Viduka, Yakubu (Ehiogu)