Centre back Rio Ferdinand opened the scoring, but United's frontline ran riot in Kyiv during a free-flowing and frenetic Group F encounter.
Despite pre-match predictions of a tight tussle likely to be settled by a single strike, the net bulged six times in the Ukraine capital as Wayne Rooney, Carlos Tevez and Cristiano Ronaldo enjoyed the freedom of the Olympiyskiy Stadium's vast pitch.
Dynamo Kyiv did score two of the six goals, but never seriously threatened United's stranglehold on a third successive Champions League victory. The win leaves the Reds with maximum points so far in this season's competition and the opportunity to secure group qualification when Kyiv travel to Manchester in a fortnight.
United's first-half performance was as good as any European display in recent memory, with the Reds carving out a number of chances in the first half-hour. With Kyiv desperate for a win and manager Jozsef Szabo adopting a three-pronged strikeforce, United found gaps aplenty in the home side's defensive armour.
Szabo's tactics left Wayne Rooney, Carlos Tevez and Cristiano Ronaldo with boundless space in which to operate and it was the Reds' no.7 who looked most menacing in the game's early stages. Tiberiu Ghioane decided the easiest way to halt the 22-year-old was illegally, but his 9th minute foul on the Portuguese winger ultimately led to United's opener.
Giggs curled the resulting free-kick teasingly into the space in front of Kyiv goalkeeper Olexandr Shovkovskiy, who remained rooted to his line. Instead, Rio Ferdinand, who scored the Reds' third at Villa Park on Saturday, met the ball early to thump home a header and send United into the lead.
It must have been tempting for Sir Alex to then issue stifling instructions to his troops, but United continued to push forward in search of a second goal. It duly arrived on 18 minutes when Ronaldo fed Wes Brown on the right hand side of the penalty area. Kyiv's Goran Gavrancic slid in to intercept Brown's first-time cross but could only divert the ball into Rooney's path, who found the net for a simple tap-in.
It was Rooney's fifth goal in his last four United appearances and no less than the Reds deserved. Sir Alex's European sides are often criticised for a lack of attacking ambition but the manager's decision to attack Kyiv so early must surely be applauded.
Indeed, United would have killed off the game a minute later had Rooney or Tevez been able to get onto the end of yet another searching Ronaldo ball. The front two then went close again when Rooney stung Shovkovskiy's palms before Tevez's shot from the rebound was bravely blocked.
Such frenetic pace could never be sustained and the match slowed, albeit marginally, until the Ukrainians pulled a goal back on 34 minutes. Anderson did well defensively to break up a rare foray into the penalty area but Diogo Rincon gave John O'Shea the slip at the resulting corner and headed home unmarked from 10 yards.
It was a poor goal to concede from United's point of view, although the Reds almost restored the two-goal advantage immediately when Cristiano Ronaldo forced Shovkovskiy into a smart save down to his right. The Reds were on the march and John O'Shea missed a gilt-edged opportunity five minutes before the break when he miscued a shot from six-yards after good work on the right from Wayne Rooney.
A third United goal did arrive before half-time and again it was Ryan Giggs who provided a telling cross from the left flank. This time it was Ronaldo in the middle and, although he was unmarked, there was still a lot of work to do. Indeed, the no.7 was forced to back-pedal quickly before leaping to direct his header beyond Shovkovskiy and into the corner of the net.
The half-time whistle provided both players and fans a chance to draw breath (but not before the Reds fashioned another chance, which Rooney blasted narrowly over the top) and inevitably the second half was slightly more subdued.
But only just. The major difference was that now the team in white were fashioning the better chances, although United's defence, marshalled superbly by Rio Ferdinand, denied the home side again and again.
Rincon saw a glancing header go just wide on 52 minutes before Carlos Correa's free-kick curled around the wall and narrowly past van der Sar's left-hand post. It did send a scare through United's travelling support, as did Nemanja Vidic when he looked to have brought down Kyiv substitute Artem Milevskiy inside the area. But Hungarian referee Viktor Kassai blew for a foul the other way and a relieved United side restarted the match.
Kassai was under the spotlight again seven minutes later when Goran Gavrancic was adjudged to have handled the ball… initially on the edge of his area. After consultation with his assistant, however, the man in the middle pointed to the penalty spot, where Ronaldo coolly sent the hapless Shovkovskiy the wrong way to notch United's fourth and effectively seal the win.
Kyiv, rooted to the bottom of Group F and with nothing to lose, weren't about to surrender and Bangoura doubled the home side's tally with a long-range rocket on 78 minutes. Despite the revival, however, Sir Alex opted to withdraw Edwin van der Sar and Ryan Giggs, with Tomasz Kuszczak and Danny Simpson given a chance to impress.
There could have been even more goals in the final 10 minutes, but in the end United ran out 4-2 winners after a thrilling, open-ended 90 minutes that gives United every opportunity to secure passage into the knockout stages when the Ukrainians arrive at Old Trafford next month.
United: van der Sar (Kuszczak 80); Brown, Ferdinand, Vidic, O'Shea; Ronaldo, Anderson, Fletcher, Giggs (Simpson 80); Tevez (Nani 73), Rooney
Subs not used: Pique, Evans, Eagles
Dynamo Kyiv: Shovkovskiy; Ghioane (Belkevich), Gavrancic, Yussuf, Diakhate; Gusev, Correa, Nesmachniy; Bangoura, Rincon, Shatskikh (Milevskiy)
Subs not used: Rybka, Rotan, Vaschuk, El Kaddouri, Markovic