England closed on 234/5 with a lead of 202 runs, mainly due to Bell\'s unbeaten and near-flawless knock of 105.
Chester-le-Street: Ian Bell cemented his status as the top batsman of the Ashes series by caressing his way to a third century of the summer on Sunday, ensuring England finished a fluctuating third day of the fourth Test well on top.
England closed on 234/5 and with a lead of 202 runs, mainly due to Bell's unbeaten and near-flawless knock of 105 - his 20th Test century and the fourth in his last five Ashes Tests.
The Australians only added 48 to their overnight 222-5, restricting their first-innings lead to 32, but they established command when paceman Ryan Harris reduced England to 49-3 shortly after lunch on a deteriorating pitch.
However, a fourth-wicket partnership of 106 between Bell and Kevin Pietersen (44) proved crucial for England, as was the fifth-wicket stand of 66 with Jonny Bairstow (28).
The match is still up for grabs heading into the fourth day, during which rain is forecast, but England will be the happier of the two teams, considering their position at the start of the day and the poor start to its reply. In a reasonably low-scoring game, the lead is significant.
England are 2-0 ahead in the five-match series and have already retained the Ashes urn. A draw or victory will win the team a third straight series over its great rival.
Bell jumped for joy and punched the air after chipping to mid-on for a single to bring up his century just before stumps, becoming the 10th Englishman to score three hundreds in an Ashes series. He is in the form of his career and has a happy knack of bailing England out.
The Pietersen-Bell stand could prove to be the most decisive of the Test, coming at a time when Harris had removed the top order in the space of 24 balls with yet another fine spell of pace bowling.
Pietersen will be disappointed with the way he got out - he tried to work Nathan Lyon square from outside off stump but top-edged the ball to Rogers at cover - but he dug in for a crucial 84-ball knock, often playing second fiddle to the artistic Bell.
Bell rarely looked like getting out on a track where you could never really feel 'in'. Two trademark steered cuts were early highlights while successive cover drives off Harris took him to his half-century, a total he has achieved in nine of his last 10 Ashes Tests.
Bairstow, who has been short of form this series, defied the critics by playing solidly alongside Bell and he came down the ground to smash Lyon for successive fours to indicate his stomach for the fight.
The teams came off for eight minutes for bad light - the Chester-le-Street ground has no floodlights - but Bell and Bairstow picked up where they left off, until the latter edged Lyon to Brad Haddin for the wicketkeeper's 24th catch of the series.
Tim Bresnan (4) was with Bell at the close.
The prognosis looked so encouraging for Australia when Jonathan Trott was third man out for 23, with England then effectively 17-3 taking account of the first-innings deficit.
Trott displayed his ongoing frailties down the legside by gloving Harris' perfectly directed bouncer to Haddin, a real result for Australia captain Michael Clarke who had arranged leg-side field placings to leave Trott vulnerable in an area that used to be his strength.
That was the culmination of a rip-roaring stint by Harris which started with an absolute pearler to bowl Joe Root (2) - the ball arrowed in, then seamed away to nick the bail on off-stump - and continued with the dismissal of Alastair Cook (22), who wafted at a wide one to be caught behind.
The top order's now-familiar shortcomings with the bat threatened to undermine a satisfying morning's work by England with the ball, with both Graeme Swann and James Anderson grabbing two wickets each before Stuart Broad completed his ninth five-wicket haul in tests.
Chris Rogers had resumed his first Test century - the "sweetest innings" of his career - on 101 from overnight but Graeme Swann found the faintest glance on the opener's glove, with the ball hitting his pad and rearing up to the short-leg area where wicketkeeper Matt Prior darted forward to take a wonderful diving catch. Australia reviewed but the much-maligned Hot Spot did its job and Rogers departed head down for 110 but to a warm ovation from spectators.
Broad sealed his five-wicket haul - and wrapped up the innings - by trapping Harris lbw for 28 in comical circumstances.
Umpire Tony Hill originally gave it not out but England reviewed and there was laughter around the Riverside ground when replays showed how plumb it was. Harris saw the video replay and didn't even wait for the official reversal of the decision, with the players already on their way to the dressing rooms by the time Hill raised his finger to an empty wicket.
Australia's bid for victory won't have been helped by a right hip/groin injury sustained by Shane Watson midway through an over he was bowling. He walked off gingerly and will continue to receive treatment. Runners are no longer permitted in international cricket.