David Moyes revealed that when he first sat in Sir Alex Ferguson's old chair, in the manager's office at Manchester United's training ground, he did it when nobody was looking "in case anybody thought I looked stupid". There is no protection whatsoever when it comes to stepping into Ferguson's shoes on the touchline, but if this first Premier League game of the Moyes era is a sign of things to come, the transition will be seamless.

It was about as perfect a start as the former Everton manager could have wished for as United opened the defence of their title with an emphatic victory that featured two Robin van Persie goals – the second an absolute beauty – and two more from Danny Welbeck, whose delightful chip in injury time means that he has already equalled his tally for last season.

Moyes stepped on to the pitch at the final whistle to applaud the travelling supporters who had spent much of the game singing his name and asking for the wave that he was more than happy to provide. It was that sort of day for the Scot, one of those afternoons when he must have felt like he could do nothing wrong, especially when he watched Wayne Rooney come off the substitutes' bench and have a hand in the last two goals. Rooney's celebrations were muted but nobody could question the commitment he showed on the pitch.

His manager was more animated, punching the air with delight when Van Persie thumped home his second and United's third, a goal that ended any hopes Swansea had of getting back into the game and silenced the home supporters to the extent that Moyes could be heard bellowing "pass, pass, pass" to his players. There is still room for improvement, as Moyes admitted afterwards, but he was entitled to feel hugely satisfied after negotiating a potentially tricky fixture with the minimum of fuss.

Moyes said that he had slept well before the game, but it would have been fascinating to be a fly on the wall in the United changing room beforehand to hear how he handled the team-talk. In Ferguson's first league game in charge, at Oxford United on 8 November 1986, the Scot's nerves got the better of him and he ended up getting Peter Davenport's name wrong. "He went through the defence and midfield and said: 'Right, up front, Frank and Nigel. OK lads?'" Davenport recalled. "There was a pause, then Robbo said: 'Nigel? Who's Nigel?' Fergie points at me and goes: 'Him, Nigel Davenport.' He'd got me confused with the actor from Howards' Way."

Moyes has had three months longer than his predecessor did to get his head around the squad he was inheriting, he has been coming up against United for the past 11 years and it would be fair to say that the names are a bit more high-profile than they were in 1986, when the team Ferguson took over were languishing 19th in the old First Division. United, for the record, lost 2-0 at the Manor Ground. "Oh, Christ almighty, I've picked a job here, all right," were Ferguson's thoughts at the time.

If there was a fair amount of interest in Ferguson's appointment, it was nothing compared to the media circus that has greeted Moyes's arrival. The world is a very different place 27 years on – the top-flight TV deal was worth £6.3m in 1986; that figure stands at £5.5bn now.

As Moyes strolled down the tunnel just before kick-off, the flashbulbs started to go off and a TV camera was thrust in his face as he stood on the edge of the technical area, wearing a black tracksuit and trainers, glancing across at the travelling supporters that would soon be serenading him.

Bigger challenges lie ahead – Chelsea visit Old Trafford on Monday week and United visit Liverpool and Manchester City in their next two away games; the Rooney saga has the potential to rumble on at least until the end of the window and possibly beyond, while the absence of a marquee signing needs to be addressed – but this was quite a way to start a new season, and a new job.