English FA Premiership/ Bolton Wanderers 1 Manchester Utd 2: Alex Ferguson has had so many sleepless nights inflicted by Chelsea he must relish the thought it is now Jose Mourinho's turn to wake in a cold sweat as Manchester United have reinvented themselves as credible challengers to the world's most richly endowed club.

United were 18 points behind when they kicked off against Wigan Athletic on March 6th. Supporters' websites and fanzines had produced articles such as "Ten Reasons Why Fergie Should Go" and, going back to December, one newspaper ridiculed Carlos Queiroz with a "Carlos the Prattle" headline after he dared to speculate that United could catch Chelsea.

Ferguson first declared the title chase void on January 3rd and as recently as eight days ago he was wrinkling his nose when asked whether United could catch Chelsea and talking instead about beating Liverpool to second spot.

Suddenly he is daring to dream again. Eight successive league victories have whittled down the gap to seven points, with six games remaining. Chelsea also boast a superior goal difference but United have the impetus and, just as importantly, they believe they can do it. "It's definitely on," Louis Saha said after playing a significant part in this victory.

The alternative argument is a lot of people are getting giddy given that, unless Chelsea go into meltdown, United have succeeded only in returning a dash of excitement back to what was becoming a procession. Try telling that to Ferguson. His body language spoke for itself as he made his way over to the away end, punching the air. It was a visible celebration, turning minds back to a 2-2 draw at Arsenal three years ago when he muddied his shoes on the Highbury pitch in a calculated attempt to unnerve Arsene Wenger's team.

The current sequence of wins has coincided with Ferguson stumbling, almost by accident, on a central midfield partnership of Ryan Giggs and John O'Shea. Giggs has flourished in his new role whereas O'Shea, whose career had been stagnating, also merits accolades for his contribution, not least the measured pass for Saha in the move for Ruud van Nistelrooy's decisive goal.

Saha had been chosen ahead of Van Nistelrooy to partner Wayne Rooney but the debate about fitting three into two will become a side issue if Ferguson continues to experiment with such distinction. Saha's equaliser, bent in with the outside of his left boot, was a moment of expertise. Equally impressive but less noted was his selflessness in setting up Van Nistelrooy for the winning goal. Van Nistelrooy swept in Saha's assist for goal 150 in his 214 appearances for the club.

A few minutes earlier Ferguson had appeared on the touchline, gesticulating furiously at Rooney for losing the ball. Rooney fell short of his usual excellence but United are not as reliant upon him as they were earlier in the season.

There was never even a hint of panic after Bolton had taken an undeserved lead, Kevin Davies nutmegging Rio Ferdinand and side-footing past Edwin van der Sar. Likewise they did not resort to lumping desperate balls into the Bolton penalty area but retained slick, first-touch passing and off-the-ball movement.

Ferguson described it as their most impressive performance of the season. Bolton's approach play seldom flustered their opponents and even Kevin Nolan, Bolton's outstanding player this season, struggled to have any impact.

Sam Allardyce, Bolton's manager, was so despondent he delegated the bulk of his duties to his assistant Sammy Lee, whose message to Chelsea was that they would be making "a terrible mistake, a schoolboy mistake" if they doubted United's powers of recovery.

Ferguson, at the very least, is winning back the sceptical United supporters. "We shall not be moved," they sang. "We are the team that's going to win the football league, and we shall not be moved."

Giggs does himself a disservice with his carping at officials but his running, poise and control contributed hugely to United's victory.

• Guardian Service