A double from Lionel Messi, his 79th and 80th goals in 2012 saw him come within five of Gerd Muller's 85-goal record in a calender year, while racking up his 56th Champions League strike, trailing only Raul's 71-goal tally and equalling Ruud Van Nistelrooy's haul.
Dani Alves opened the scoring with a fine half-volley, and despite a few opportunitires for Spartak, Messi made it 2-0 just before the half-hour mark with an opportunistic finish from a rebound.
The Argentine finished off a quintessential Barca passing move to score his second of the night towads the end of the first half, with only the heroics of Andriy Dykan preventing the Blaugrana from adding to the scoreline after the interval.
Barcelona now move onto 12 points in Group G, meaning that they cannot be caught by third placed Benfica, while Spartak sit bottom of the standings on three points, but still have a chance of overtaking the Portuguese side and qualifying for the Europa League.
Fit-again Carles Puyol was dropped to the bench from the side that defeated Zaragoza 3-1 on the weekend, with Javier Mascherano replacing him. Alves Sergio Busquets and Cesc Fabregas also returned to the starting XI in place of Martin Montoya, Alex Song and David Villa.
Spartak meanwhile readied veteran Dykan just in time to mind the net against the Catalans, after injuries to Sergei Pesyakov and Artem Rebrov had left them scrambling to find a fit goalkeeper.
The home side set up in a deep 5-4-1 formation to prevent Barca from playing in behind, but that only seemed to invite attacking pressure from the Catalans, which in turn left gaps to be exploited in the midfield.
A sublime clip from Xavi eight minutes in was taken brilliantly by Pedro on his chest, but his volley was parried at point blank range by Dykan. Not long after, a well worked move from a corner saw Dmitriy Kombarov blast over the bar from 10 yards out.
Barca were ahead just after a quarter of an hour though, as Messi, despite being surrounded by a throng of defenders, did enough to ping to Alves on the edge of the area, who drilled a precise half-volley into the bottom corner.
Spartak nearly struck back within minutes, but after Emenike did well to send a cross right onto the penalty spot, Marek Suchy should have done a lot better than slicing harmlessly over the bar from an unmarked position.
The Russians were given a lesson in ruthlessness 27 minutes in, as Barca raced into a two goal lead. Iniesta saw a shot saved by Dykan after cutting in near the byline, but Messi was first to the rebound, and lashed into the corner.
But still Spartak had their chances to get back into the game. Kombarov found space on the left flank on the break, and sent an early cross behind the defensive line towards Emenike, but the Nigerian skied over the bar, a recurring theme for Spartak.
And true to form, Barca soon made the Russians rue their missed chance. The Blaugrana toyed with the Spartak midfield with a series of sublime, quick passes, before Pedro released Messi for the dagger blow, the Argentine rounding Dykan to slot home.
The chances continued to fall Barca's way in the second half. A one-two with Cest Fabregas and Iniesta saw the former denied by Dykan from close range, before Messi's cross found Pedro unmarked in the six-yard box, but his header was straight at the kepeer.
Spartak were floored throughout the second half, and simply could not get much going as the tiki-taka machine from the Catalans kept them perpetually on the back foot.
Messi and Pedro each had late chances to add a fourth goal, but Dykan was alert on both occasions to prevent the Blaugrana from scoring further. It mattered little though, as Barca breezed through to the final whistle and took their place in the knockout stages for yet another season.