Defending champions Manchester United gained their first Premier League home win of the season - and left near neighbours Bolton nursing a huge sense of injustice as they made their way back up the M61 after a 2-0 defeat.

United's margin of victory may have been deserved but the manner of Cristiano Ronaldo's opener left a sour taste for the Trotters as referee Rob Styles amazingly gave the hosts a penalty when Jlloyd Samuel clearly played the ball when he slid into Ronaldo just before the hour mark.

Substitute Wayne Rooney also found the net for the first time this season, curling home superbly after exchanging passes with Ronaldo to give the margin of United's triumph a more comfortable look.

But Bolton boss Gary Megson will know his side were frustrating their hosts until Styles' dramatic intervention.

Just 24 hours after he warned his fabulous array of attacking talent they could expect to be rotated on a regular basis, Ferguson left Rooney on the bench.

In fairness to the England striker, whose form has been below par during the opening weeks of the campaign, his manager probably reasoned Dimitar Berbatov and Carlos Tevez could start to develop some sort of partnership against Megson's side.

Although Bolton did claim a couple of notable Old Trafford victories during Sam Allardyce's reign, if any side looked ripe for registering a first home win of the season against, Bolton was it.

Yet it did not quite work out as Ferguson planned.

For a start, Bolton were not as unadventurous as many believed and when, after about 15 minutes, United did get into their stride, they found it difficult to break through a hard-working defence, aided superbly by the midfield industry of Gavin McCann.

Jussi Jaaskelainen was called upon on half a dozen occasions but most of his saves would be regarded as routine for the Finn, including the low Ronaldo free-kick he kept out at his near post.

On his first Premier League start since last May, Ronaldo took plenty of responsibility for United's goal search on his shoulders but while Tevez and Berbatov tried hard, there was no sense of a partnership between the pair.

The only time they were involved in anything meaningful was when they helped set up Rio Ferdinand. But the centre-half bounced his half-volley straight at Jaaskelainen.

Bolton could not claim to have posed even half the threat United had done. But they had established themselves as an attacking force long before Fabrice Muamba was presented with the best opportunity either side had to break the first-half deadlock.

As a former pupil of Arsene Wenger's at Arsenal, Muamba could at least have been expected to force Edwin van der Sar into a save when Gretar Rafn Steinsson's low cross rolled invitingly into his path after Ferdinand had slid in with Kevin Davies at the near post.

Inexplicably, from barely 10 yards, the England Under-21 international was so badly off target his shot nearly rolled out for a throw-in.

Having got trips to Liverpool and Chelsea out of the way during an incredibly tough start to the season, now Ferguson was expecting his team to start winning.

But as the hour mark approached the opener still proved elusive, despite the improved efforts of Ronaldo.

Yet even Ferguson must have felt a bit sheepish when Styles, perfectly placed, watched Samuel make what everyone in the stadium seemed to think was a perfectly timed tackle on Ronaldo, then point to the spot as the home player hit the deck.

Bolton could not believe it. TV replays justified their incredulity. Ronaldo simply stepped up and sent Jaaskelainen the wrong way.

The introduction of Rooney and Paul Scholes came not long afterwards.

Given his desire to play every minute of every game, Rooney was presumably not happy at being left out, so there must have been an element of `I'll show you' about his superb curling shot which found the bottom corner after a neat exchange of passes with Ronaldo 13 minutes from time.

Scholes went close to increasing United's lead at the end but by then, the damage had been done for Bolton.