Kevin Strootman scored on the stroke of full-time to save Roma from their first defeat of the Serie A season, but his goal was only good enough to salvage a 1-1 draw at Atalanta as the capital club's title challenge continued to stall.
The Giallorossi won 10 games on the spin to blaze an early trail that left champions Juventus and ambitious Napoli playing catch-up, until their record-breaking streak came to an end with a draw at Torino.
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Stalemates against lowly Sassuolo and Cagliari followed before Atalanta threatened to call time on their unbeaten run with a second-half free-kick from Davide Brivio.
Summer signing Strootman would finally get the better of outstanding home goalkeeper Andrea Consigli at the death, sparing Roma's blushes, but a fourth consecutive draw means Rudi Garcia's men will be three points adrift of Juve should the reigning champions beat Udinese later on Sunday.
The capital club seemed determined to make amends for recent poor form at the Stadio Atleti Azzurri d'Italia, Marquinho forcing a difficult save from Consigli before Strootman let loose from just outside the box.
Atalanta were not ready to roll over to southern opposition, however, and steadily began to take charge of the game.
Carlos Carmona looked to fire the hosts ahead, his innocuous finish ending up in Morgan De Sanctis' arms, but the Roma keeper was grateful when Franco Brienza's sliding effort slammed off a post.
Roma were both short on ideas and struggling to get the better of defenders Michele Canini and Brivio, who consistently protected the consistently impressive Consigli from harm.
The Giallorossi tried to get over the top instead, Dodo launching a ball forward for Gervinho only for Consigli to sweep up.
The Ivorian striker found himself in the area once more before the break, to no avail as Riccardo Cazzola hooked the ball to safety.
Six minutes after the restart, Atalanta took the lead.
Brivio had excelled in the backline and made an invaluable contribution in the final third as he drove a daisycutting free-kick under the Roma wall and beyond De Sanctis' reach.
Despite being given a wake-up call the Giallorossi remained timid in Bergamo and Michael Bradley's failure to keep possession on a forward run was typical of their new malaise.
Strootman did, however, sting Consigli's fingers with an angled sighter from distance in the 67th minute, and Roma won a corner.
Substitute Adem Ljajic was best-placed to try his luck from the set-piece and drove violently, but without precision, on his favoured right boot.
Bradley had the ball in the back of the net in the 76th minute, but the offside flag quelled any celebrations, which might have arrived 10 minutes later if not for more heroics from Consigli.
This time Miralem Pjanic delivered a pinpoint cross into the box for Alessandro Florenzi, whose header looked bound for the bottom corner, but Atalanta's keeper managed to scuttle the ball away with his feet.
It would not, however, be an afternoon to remember for Consigli and his team-mates, who remain 11th in the table, as Strootman broke their resolve moments before the final whistle.
The Serbian Ljajic pulled the strings in the final third to pick out his Dutch colleague in the area, Consigli soon slumping to the ground in defeat after watching the ball sail past his head.