Goals two and three were almost identical, owing everything to anticipation and striker's intuition as Solskjaer peeled to the near post to score with headers from David Beckham setpieces in the 39th and 64th minutes.
Van Nistelrooy, never one to be outdone, scored late in the game but this match belonged to the eternal understudy and Solskjaer's contribution to nudging his team's season back into gear last night cannot be overstated.
With Giggs producing one of the finest recent examples of modern wing play - if there is such a thing - United were irresistible, their dominance over their local rivals embarrassing.
Last night's display only re-emphasised United's dis-regard for the FA Cup.
On Saturday at Middlesbrough, they were insipid, listless and impotent. Last night, they were insatiable, utterly unforgiving and professional.
Bolton - seeking a repeat of the 2-1 victory that gave the Premiership a first glimpse of United's bility in mid- October - began well and who knows what may have ensued had Fredi Bobic not hacked Michael Ricketts' cross wide from three yards in the fifth minute?
That encouraging start was not to last, however, as Ferguson's team squeezed the life from Bolton with wonderful counter-attacking football.
Scattered around the four goals were more chances as Giggs (three times), Roy Keane and Beckham all went close.
Giggs in particular was mesmerising. Free from a recent bout of flu, he resembled a colt let loose in a meadow for the first time as he darted up and down the left flank - inside then out-side - all night long. He didn't score but he deserved too and on another night, the man- of-the-match champagne would have been his.
His form and fitness remain crucial to United's ambitions. Talk all you will about Beckham and Juan Sebastian Veron, but Giggs brings this team alive.
It was hard not to feel pity for Bolton. Manager Sam Allardyce will not want general sympathy but he will get it, for the team that led the Premiership in September are in danger of relegation.
Having not won in the League since November 18 and without a home Premiership victory since August 27, disaster looms large.
They had their chances last night and twice Fabien Barthez denied Ricketts with the score at 2-0. A goal then would have made a game of it and in some ways Bolton contributed to their own downfall. Allardyce's team made too many errors when in possession and were wasteful in front of goal.
Perhaps it wouldn't have mattered anyway.
On this form, United always seem to have another gear. With Solskjaer and Giggs in outstanding form, they were just too good.
