The Bolton goalkeeper Jussi Jaaskelainen had to make a string of decent saves from distance at the Reebok Stadium but United hardly created anything before Carlos Tevez crossed for Dimitar Berbatov to head in from six yards in in the 90th minute.
When United returned from the World Club Champonship in Japan last month they were seven points behind Liverpool but five consecutive wins have erased that advantage and they are now a point above Rafael Benitez's team.
They may have equalled Chelsea's record of 10 consecutive clean sheets in the Premier League but, ominously for their title rivals, they can still make significant improvements at the other end.
Ferguson had a smile on his face when he claimed he would take a 1-0 win in every game but there is a workman-like relentlessness about them this season and now they have managed to move top, it would surely be folly to bet against them equalling Liverpool's record of 18 league titles.
'1-0 to United' hardly has a ring to it but this was Ferguson's team's seventh victory by that margin in the league this season and he said: 'It means that the concentration is good. You have to keep good concentration in the game and I think we're doing that very well.
'I thought we played well. Bolton are a very difficult team to play against and in a local derby you're always happy to win the match but we left it very, very late.
'I don't think it's decisive but it's always nice and it's the best place to be, there's no question about that. Liverpool have a game against Everton on Monday night and even though it's for two days, we can reflect on a very good period for us.'
Performances you can question, but in terms of results, which is all Ferguson is worried about, there is little argument with that claim.
Cristiano Ronaldo was employed on the left flank at the Reebok Stadium and had little early impact as United struggled to impose themselves on a stubborn Bolton team.
It was the hosts who carried the greater early threat with Ricardo Gardner skipping past Michael Carrick and Gary Neville before shooting wide, while the impressive Fabrice Muamba also had a dipping drive swatted away by Edwin van der Sar after a powerful run.
The champions were still struggling to find any penetration but Jaaskelainen did well to turn away a Ronaldo free-kick that came through the wall, as well as a long-range effort from Anderson.
Bolton continued to threaten with Kevin Davies heading onto the roof of the net from a Jlloyd Samuel cross. Even the arrival of United's veteran pairing failed to make much difference with Jaaskelainen pushing away Ronaldo's free-kick, Scholes having a volley blocked and Tevez heading straight at the goalkeeper from a Giggs cross.
Ferguson had toyed with the idea of replacing Tevez with the youngster Danny Welbeck for the final couple of minutes but was glad he did not when the ball fell for the Argentinian who crossed for the un-marked Berbatov to head in from six yards for his fifth goal in the league for United and his first away from Old Trafford.
Gary Megson, whose team have failed to score in four games, described it as 'an important goal but a poor goal' but rates United as favourites for the title.
He said: 'They usually come good in the second half of the season and Chelsea have done well too but that's what good teams do. They keep going, they trust the way that they play but whoever does finish above United, if they do, will win it.'