After a similar feeling of euphoria after a victory in last season's first home game, Manchester United fans will try to check their expectations after Sunday's 4-0 win against West Ham.
It was the best performance of Jose Mourinho's time at Old Trafford, better than the one against West Ham in the EFL Cup last season. His side were excellent, with the powerful Romelu Lukaku scoring twice on his debut; he has now scored 11 in 11 against West Ham.
Nemanja Matic was man of the match in his first league game, intercepting, tackling, swiveling, blocking, dribbling, shooting and launching a counterattack after turning past two defenders before half-time and then threading a ball beyond two midfielders. Where's the logic in Chelsea selling him to one of their main rivals?
There were positives all over the pitch. Anthony Martial was on for 10 minutes and managed to score and assist. Paul Pogba performed, passing well and driving his team forward in a manner not seen enough during the stolid reign of Louis van Gaal and even many Mourinho matches.
United's 1-1 draw against West Ham at home in November 2016 was typical of many Old Trafford performances last term. Possession heavy and plodding, United couldn't score. On Sunday, the new-look Jose's giants scored four times without reply. Even the manager, sporting a smart shirt and suit jacket rather than a manager's quilted coat, looked reinvigorated.
The mood, as it often is on the opening day of the season, was positive. Legendary captain Bryan Robson unveiled a mural of his finest hour, being carried off the pitch by fans after a 3-0 win over Barcelona in 1984. Robson really enjoyed mixing with rank-and-file fans on the concourse beneath the stand. He's usually glad-handing executive fans before matches in his role as a United ambassador.
Fans also sang for Roy Keane and a host of former players. The songbook tends to come out when fortunes are favourable on the pitch.
Defender Phil Jones played well, as he does when he avoids injury. He doesn't get injured on purpose, but is it too much to ask for him to play 20 games alongside Eric Bailly to see what their partnership is really made of?
Marcus Rashford was a live wire who was encouraged to run at pace towards opponents like the unprotected Pablo Zabaleta, though the Mancunian needs to find his range when shooting. It will come, as it will with Pogba.
Antonio Valencia, who is incredibly proud to be captain and who now speaks to his teammates in English on the pitch -- Mourinho is fine with them speaking Spanish in the changing room, but wants English to be spoken on the field -- is rightly considered a key player, but he doesn't need to go into every tackle as if he wants to take his opponent out for life. He already apologised for one sending-off in preseason in Salt Lake City.
Henrikh Mkhitaryan, who was privileged to be chosen when Ander Herrera was on the bench, continues to look the part and his free kick set up Lukaku's second. A clever ball from the Armenian also set Martial free in the 87th minute for United's fourth.
A good day at the office, then, but let's not get too carried away. Manchester United should be beating West Ham at home, especially when the Londoners have such a wretched defence. Judgments will be better after 10 games, to see where United are in the league and the Champions League, for as we saw last week in Skopje, United are well short of the standard being set by Real Madrid at present. But who isn't?
But there was a similar mood a year ago, which was deflated when Manchester City came to Old Trafford and won the derby at the start of September. That was the last time United lost a game at home, some 30 matches ago. Mourinho's men are hard to beat, but draw too often at home. Hopefully the four goals will have blown away the doubts and lifted the confidence among players and fans.
There have been a couple of false dawns in the post-Sir Alex Ferguson years at Old Trafford, but Mourinho is genuinely confident. He has had a year getting to know his players, he's largely happy with his squad but he'd not turn his nose up at another signing. His signings have mostly impressed, even if they've needed time to adjust. Defender Victor Lindelof can take hope from the experience of Mkhitaryan. He'll play when his manager considers him ready, and he'll join a team that is starting to look like one. David De Gea is one of the best goalkeepers in the world; Bailly looks like he could become one of the best defenders.
Marouane Fellaini will not become one of the best midfielders, but he has his uses and enjoys the trust of his boss. The Belgian came on with 15 minutes to play to shut out the Hammers towards the end, the job done, but not before two more goals from Martial and Pogba, which resulted in more "City reject" chants at goalkeeper Joe Hart.
With Chelsea losing and Liverpool drawing, it was a good weekend for United. The team now have a first week at Carrington since preseason started, time at home to train and prepare for Saturday's early kickoff at Swansea. It's a good barometer for United have played at Swansea twice early on in a season. In David Moyes' first game, United scored four, yet that didn't herald a decent season. A year later, Louis van Gaal's men were beaten as Sergio Romero had his only poor game for United.
The 2,015 Reds who'll make the five-hour journey to South Wales will be required to make a 6 a.m. start. Given the enthusiasm that is likely to envelope the team this week, that shouldn't be a problem.