United created chance after chance as Nani fired just wide and Anderson failed to register his first goal for the club when presented with an easy opportunity.
Upson fought manfully to stem the tide but United's class was simply overwhelming them.
And the inevitable second goal came on 29 minutes when Anderson caressed the down the left and, after flummoxing Collins with a breathtaking moment of skill on the by-line, Berbatov squared for Ronaldo to slot in his second.
United continued to keep West Ham on the back foot until the break, and Zola's half-time team talk and changes did at least see his side fight under in the second half.
Hayden Mullins made a crucial block on the ever-willing Carlos Tevez in the penalty area, and a posse of Hammers defenders had to combine to block his progress minutes later.
Bad spell will be short-lived - Zola
Bellamy did rouse West Ham's travelling contingent with a 45-yard free-kick which dipped just over United's crossbar, as he tried to catch Tomasz Kuszczak off his line.
But substitute Wayne Rooney came on for Nani with 20 minutes remaining and soon had Green pushing a deft chip over his bar and scrambling to block a vicious drive.
Boa Morte was put through by Bellamy's floated pass over the top of the United defence but knocked a weak effort into Kuszczak's arms.
The Hammers did also make a couple of late counter-attacks amid a flurry of substitutions but, time and again, their final ball was not good enough.
Manchester United assistant manager Mike Phelan: "We felt we should have attacked the game more and gone for more goals. We weren't as comfortable as we should have been in the second half.
"Berbatov showed his credentials and that piece of skill was the highlight of the game.
"We need to keep the run going and the players realise that goal [difference] could be important at the end of the season."
West Ham boss Gianfranco Zola: "They are the champions of Europe so it's difficult but at least they gave everything in the second half.
"My players deserved a goal in the second half but Sears and Collison came on and did very well.
"I have a great belief in my players, I trust them very much, and I am sure this bad spell will be over soon."
Man Utd: Kuszczak, Rafael Da Silva (Neville 81), Ferdinand, Vidic, Evra, Ronaldo, Fletcher (Carrick 69), Anderson, Nani (Rooney 70), Tevez, Berbatov. Subs Not Used: Foster, Giggs, Park, O'Shea.
Goals: Ronaldo 14, 30.
West Ham: Green, Faubert, Collins, Upson, Ilunga, Behrami (Boa Morte 44), Bowyer (Sears 69), Mullins, Etherington (Collison 46), Di Michele, Bellamy. Subs Not Used: Lastuvka, Lopez, Davenport, Reid.
Booked: Collison, Collins.
Ref: Peter Walton (Northamptonshire).
BBC Sport Player Rater man of the match on 90 minutes: Manchester United's Cristiano Ronaldo - 8.71 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.
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