Young maintained the defending Barclays Premier League champions' tradition of leaving it late to grab the winner by setting up Steven Reid's own goal at the Hawthorns.
Although not an injury-time effort like the one Nani produced to defeat Manchester City in the Community Shield a week earlier, there was less than 10 minutes on the clock when the Red Devils grabbed their winner at West Brom.
What a start: Ashley Young set up two goals on his United league debut
Young's attempt to claim his first United goal seems certain to end in failure given his cross-shot was off target until it struck the unlucky Reid and ended up creeping past Ben Foster.
More importantly for Young and his team-mates, though, it got United's title defence off to a winning start.
'I would rather goals came before then,' said Young. 'But it is always special when goals come late. Then you have to defend the lead, which is what we did.
'It was always vitally important to get off to a winning start.
Wrong goal: Steven Reid (centre) finds his own net after Young's cross
'A lot has been said about our away form last season. If we can build on this result, I am sure we will be out to retain the title again.'
As United only won five times away from Old Trafford last term, they look likely to better that tally already.
Indeed, it was not until their last visit to the Hawthorns on New Year's Day that Sir Alex Ferguson registered their second away success.
This season, they appear far more plausible challengers, a fact acknowledged in their status as favourites and virtually unanimous selection to retain the crown.
On target: Wayne Rooney scored the opening goal at the Hawthorns
Going forward, there is certainly a fluency that has been lacking since Cristiano Ronaldo's departure. It was in evidence again as Young set up Wayne Rooney for his 12th-minute opener.
'The team has been doing that throughout pre-season," reflected Young. 'It was a great team goal.
'We wanted to capitalise on that and continue our good work but couldn't get that second goal.
'We were always going to create chances though and eventually we got the winner. I will try to claim it but it is more important to get the three points.'
West Brom 1 Manchester United 2: Ashley saves De Gea after another goalie gaffeRooney is back to his best and that must lastJamie Redknapp's Weekend Watch: Sympathy for Gervinho and the return of Torres Ferdinand blow and De Gea howler but United still roll on with late win