After Robin van Persie's hat-trick against Olympiacos fired David Moyes' men into the UEFA Champions League quarter-finals on Wednesday, Rooney - stand-in captain due to Nemanja Vidic's suspension - gave everyone a timely reminder of his match-winning ability at Upton Park on Saturday.
Rooney was employed in a more advanced role due to Van Persie's absence with a knee injury, and the 28-year-old broke the deadlock with an ingenious looped half-volley from almost 50 yards in a goal reminiscent of David Beckham's memorable strike against Wimbledon in 1996.
It was fitting that the former England captain was in attendance to witness the goal, watching from the stands, and Beckham saw Rooney add a second after 33 minutes when the ball fell to him fortuitously eight yards out.
Rooney had the chance to complete his hat-trick nine minutes after the break when he met Ashley Young's cross with a looped header, but United had to settle for the two-goal cushion.
Moyes was able to reflect on a rare successful week in a season of disappointments in his maiden campaign at Old Trafford, while Sam Allardyce's West Ham are not yet out of relegation trouble, though they remain six points clear of the drop zone in 14th.
The visitors could have moved ahead as early as the third minute when Marouane Fellaini's downward header was cleared just in front of goal by Andy Carroll.
But the away fans were soon celebrating Rooney's wonder-goal five minutes later.
The England international spotted goalkeeper Adrian off his line and struck an audacious half-volley from almost the half-way line, with the ball looping over the flailing Spaniard before bouncing into the roof of the net.
With Upton Park still stunned, Juan Mata then led a swift breakaway in the 25th minute and picked out Shinji Kagawa on the left, but the Japanese fired straight at Adrian.
West Ham were causing problems of their own from wide areas and captain Kevin Nolan saw his penalty appeal for a tussle with Darren Fletcher waved away by referee Lee Mason in the 33rd minute.
That proved to be a double blow for the home side as, from the resulting counter-attack, Mark Noble cleared Young's cross straight at Rooney and he took advantage of the good fortune with a cushioned side-foot finish.
West Ham made a sprightly opening to the second period without troubling the Manchester United goal.
After settling into the half, Rooney missed the chance for his hat-trick by floating a header wide from Young's cross in the 54th minute.
Young was involved again 11 minutes later as his whipped cross was headed over the crossbar by Fellaini, who was put under pressure by James Collins.
Rooney was replaced by Javier Hernandez in the 77th minute and left the field to a rapturous reception from the visiting supporters, as United comfortably saw out the closing stages.
Fellaini had a tentative claim for a penalty in the closing stages when he went to ground under Antonio Nocerino's challenge, but Mason was unmoved.
