The victory gives the Giallorossi their first clean sheet and more importantly a first home win of the season.
Zdenek Zeman made the bold move of dropping Daniele De Rossi, Pablo Osvaldo and Nicolas Burdisso to the bench. De Rossi's demotion came after a reported bust-up with the Czech tactician after last weekend's drubbing by Juventus.
Leandro Castan, Marquinhos and Ivan Piris made up a very different Giallorossi backline, while Mattia Destro and Lamela formed the forward trident with Francesco Totti. Bradley made his first start since his injury layoff.
Atalanta were forced into fielding a whole new backline as Guglielmo Stendardo, Daniele Capelli, Davide Biondini, Thomas Manfredini, Carlos Carmona, Ivan Radovanovic and Ferreira Pinto were all absent, and Stefano Lucchini sat out a ban.
Fans were treated to wave after wave of attack in a free flowing game. Roma came out of the gate like a bull in a china shop, with Bradley firing straight at Andrea Consigli.
On ten minutes, Atalanta exposed Roma's high defensive line, when Ezequiel Schelotto poked through to send German Denis clear. Maarten Stekelenburg did well not to buy the forward's dummy and saved well, before Marquinhos got back to clear a rebound.
Roma's shot-stopper was kept busy, as he saved a Federico Peluso header from a Maximiliano Moralez set piece, then saw Denis fire wide from several yards out.
The visitors continued to misfire when, on 17 minutes, an inviting Giuseppe De Luca cross was volleyed on to the crossbar by Moralez from only six yards out.
Roma scored against the run of play on the half hour mark. Totti showed great vision to dink a delightful ball through to Destro, who deceived Consigli by rolling the ball into the net off his ankle.
The Giallorossi should have had a penalty three minutes later, but Moralez' clumsy challenge on Lamela went unpunished.
Three minutes before half time, Stekelenburg palmed Luca Cigarini's dipping shot around the post. At the other end, Totti freed Federico Balzaretti down the left flank, but Lamela failed to throw himself forward to meet the resulting cross.
Roma should have doubled their advantage on the stroke of half time. Lamela flicked on a diagonal ball from Balzaretti, but Destro volleyed it onto the bar. Destro pulled his shirt over his head as he knew he should have done better.
The hosts continued to press after the restart. Alessandro Florenzi volleyed wide, before Consigli turned a Totti drive from 40 yards over the bar. The Roma talisman proved there's still life in his old legs as another effort skimmed the bar.
Roma finally doubled their lead just after the hour. Consigli parried a Destro drive into the path of Bradley, who stroked home from an acute angle.
Destro pushed for a third goal, but Consigli saved with his foot. Atalanta exposed Roma's creaky defence once more as Denis finally put the ball into the net. However, the strike was wrongly chalked off for offside, with replays clearly showing Marquinhos keeping Denis onside.
Both sides continued to attack until the end, as Consigli denied Totti the goal he was desperately craving yet again.
Roma: Stekelenburg; Piris, Marquinhos, Castan, Balzaretti; Florenzi, (Marquinho 85) Bradley, (Perrotta 72) Tachtsidis; Destro, Totti, Lamela
Atalanta: Consigli; Raimondi, Matheu, Peluso, Brivio; Schelotto, Cigarini, Cazzola, (Scozzarella 72) Moralez; (Bonaventura 60) De Luca, (Marilungo 65) Denis
Goals: Lamela 30 (R) Bradley 62 (R)