Wayne Rooney's departure to home-club Everton will be a major miss for the former Premier League champions. But, there is a serious need for them to get off to a solid start, pick up three points and mount their title challenge in the right manner.
United scored the least goals of the seven teams to qualify for Europe from the Premier League last season at 54, 32 fewer than the highest in Tottenham. In Mourinho's last Premier League triumph, the Blues from London won it easily, trotting towards the finish line since February. Romelu Lukaku rose above the West Ham defence to put away a powerful header.
Moments later Paul Pogba fired in the fourth after he was slipped in by Martial to complete the rout to the delight of the home support. He also had Patrice Evra playing as a left wing-back and he had great energy going up and down the left hand side.
The English veteran has echoed his manager with setting the bar higher for his club this season but insists the squad is better off than a year ago.
And the Armenian made it two assists for the day a few minutes from time as he played in substitute Anthony Martial with a attractive first-time pass. Matic will fit and be mobile. Worse case scenario, he'll give you a six.
A new signing at Manchester United, Lindelof has not settled too quickly.
A wide man has always been of interest, but Mourinho claims he is also looking for a left-back, even though he admires Luke Shaw's attitude in coming back from another injury and the England defender will be given a chance to re-establish himself.
"On the other hand, Pep Guardiola sometimes neglects the defensive side of things on the premise that all-out attack will conquer any defence and they will win more games like that".
It also consigned the Hammers to bottom place in the first, if largely irrelevant, league table of the season, but perhaps more significantly quelled the optimism from a positive summer, fuelled by the recruitment of experienced top-flight players.
Jose Mourinho is ready to chase trophies again in his second season with Man United. While United's was good, West Ham didn't have the best of preparation heading into the season.