The 22-year-old Spanish livewire scored the opener and played a big part in compatriot Fran Merida's first league goal as Arsenal moved to 45 points with United, who have played a game more, on 47 and Chelsea on 48 after they both enjoyed convincing victories on Saturday.
Another two-goal victory when Arsenal play Bolton at home in a re-arranged fixture on Wednesday would put Arsene Wenger's side on top of the table for the first time since August.
"It's unusual to play the same side twice in three days," Wenger told Sky Sports. "Bolton gave a lot today and so did we so both teams will have the same problem to recover."
Aston Villa became the latest top-four challenger to squander an opportunity when they were held to a disappointing goalless draw by West Ham United and Fulham's poor away form continued with a 2-0 defeat at Blackburn Rovers.
The battle for the final Champions League qualifying slot is as wide open as the scrap for the title but the four clubs best-placed to fight it out all faltered.
Tottenham Hotspur occupy fourth on 38 points but they were held 0-0 at home by Hull City. Manchester City are fifth, also on 38, after losing for the first time under Roberto Mancini, 2-0 at Everton, with Villa sixth on 36.
Liverpool are seventh on 34 following their 1-1 draw at Stoke City.
After watching Chelsea and United rack up 10 goals the pressure was on Arsenal to win at second-bottom Bolton who were under the eye of new manager Owen Coyle for the first time after he quit as Burnley manager.
Coyle managed a home draw with Arsenal this season while at Burnley and, as expected, his players began full of intent and ruffled the visitors at the Reebok Stadium with Ivan Klasnic having a goal chalked off for offside.
PENALTY CLAIM
Fabregas had a decent penalty claim turned down when he fell under challenge from Bolton goalkeeper Jussi Jaaskelainen. The midfielder was at the heart of all Arsenal's best moments and it was no surprise when he gave his side the lead with his 10th Premier League goal of the season.
There seemed no way through a forest of bodies in the 28th minute but after a spot of pinball on the edge of the area Fabregas combined brilliantly with Eduardo before drilling a low shot into the corner.
Bolton always looked capable of replying and should have done so after the break when Matt Taylor fired wildly over the bar after being played in by Klasnic.
Arsenal sealed the points with 12 minutes remaining. Fabregas made a surging run towards the Bolton area and the ball was eventually played across goal by Eduardo where Merida pounced from close range.
Earlier, Villa lacked inspiration against a West Ham side who started the day in the relegation zone but ended it just outside the bottom three on goal difference.
Ashley Young, Gabriel Agbonlahor and Stewart Downing had half-chances for Villa while West Ham ke
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