Summer signing Tiago Ilori made an encouragingly solid Reds debut as Alex Inglethorpe's side cancelled out strikes from Alejandro Rodriguez-Gorrin and David Moberg Karlsson through low drives by Jack Dunn and Alberto.
Raheem Sterling handed Liverpool the lead with an effort that bobbled narrowly over the line before the heroic Alberto ensured that the Reds couldn't be caught with a composed header and penalty.
Brendan Rodgers was in attendance to see his deadline day acquisition in action, while former Reds Michael Owen and Steve McManaman also travelled to see the thoroughly exciting match.
England U21s manager Gareth Southgate added himself to the list of familiar faces at Anfield as he ran the rule over the likes of Sterling, Jordon Ibe and Martin Kelly.
The opening stages of the encounter proved to be tightly contested, with both sides producing wayward efforts that failed to trouble either goalkeeper.
Attempts from Black Cats centre-backs Scott Harrison and Thomas McNamee soared well over the crossbar, while Reds wingers Sterling and Ibe both drilled shots that were equally fruitless.
Following several off-target attempts, the first shot directed towards goal - courtesy of Sunderland - broke the deadlock on the half-hour mark.
The Reds defence failed to clear sustained pressure from the visitors and were punished by a well-struck drive from the edge of the area by Rodriguez-Gorrin, who rifled beyond the outstretched arm of Danny Ward and into the bottom corner.
Liverpool nearly drew themselves back on terms in stunning circumstances through the somewhat unlikely source of Jon Flanagan.
A cross ricocheted into the path of the unmarked full-back and he responded by volleying the floating ball agonisingly wide.
The inevitable frustration of coming so close was compounded when Sunderland doubled their lead through some slick movement.
Moberg Karlsson latched onto an incisive through ball before calmly rounding Ward and prodding in from an acute angle.
That produced the desired response from Inglethorpe's youngsters as Dunn halved the deficit on the stroke of half-time. The front-man met captain Kelly's low cross with a calm clipped effort that found the far corner.
Dunn's goal proved to be the catalyst for a rampant second-half beginning from the home side as they overturned the scoreline within seven minutes of the restart.
Despite surging into the box, Alberto remained composed in possession before playing a quick passing exchange with Sterling that allowed the Spaniard to side-foot a solid effort past Joel Dixon to level the scoring.
Two minutes later, the Reds dramatically broke into the lead through the combination of Ibe and Sterling.
The former charged into the opposition's box and around Dixon before cutting back to Sterling, who managed to roll the ball just over the line under intense pressure.
A minor mar on the U21s' evening followed, when defender Lloyd Jones was shown a straight red card for an altercation with Mikael Mandron.
Sterling came close to increasing his and Liverpool's tally soon after but was harshly denied by the woodwork.
The 18-year-old's electric pace saw him race past multiple challenges before his slightly dragged left-footed shot bounced back off the post after beating the Sunderland custodian.
The home side were eventually rewarded for their continued efforts to extend their lead when Alberto found his second with just under 20 minutes remaining.
A long ball played over the Black Cats' backline was expertly controlled by the 20-year-old, whose initial shot ricocheted off the diving Dixon and back into his path - making it easy for Alberto to calmly nod the ball into a gaping net.
With just eight minutes left in a thrilling battle, the frightening speed of Sterling drew a penalty for the Reds after he was brought down by the Sunderland 'keeper.
Alberto assumed the penalty duties and sealed his hat-trick as his spot-kick crept under the arms of Dixon and into the corner of the net, ensuring Liverpool ran out comfortable and deserved winners on the evening.