Cagliari were unable to capitalise on a farcical own goal and Luigi Giorgi's late dismissal as Atalanta ground out a draw at the Stadio Atleti Azzurri d'Italia.
The Rossoblu arrested a six-game losing run with victory over Genoa last time out and Michele Canini's own goal looked to be sending them on their way to three more points in Bergamo.
But Guglielmo Stendardo led from the back to book Atalanta a share of the points with his second-half header, with Daniele Conti missing a dramatic chance to win it for Cagliari after Giorgi saw red late on.
It was a less than auspicious start for Atalanta, who found themselves a goal down within two minutes thanks to a moment of madness from Canini.
Marco Sau wriggled free of the backline to drive a cross into the home box, Canini staggering over his own feet allowing the ball to trickle into his own net.
Atalanta were keen to mask their defender's embarrassment but Giorgi managed to miss the target when it had been easier to score.
Victor Ibarbo was Cagliari's main outlet but Michele Ferri made a last-ditch stop on a fine run from the Colombian.
Giacomo Bonaventura twisted his body to strike at goal as Atalanta improved, Michael Agazzi touching the ball out for a corner, and soon Stendardo came close to glancing the ball home in a goalmouth scrum.
German Denis looked to have found himself with a free shot on goal before the break but his final touch left much to be desired.
There was time for one last Cagliari raid, though, and Giorgi put his body on the line to deny Sau when the tricky Cagliari forward had left Stendardo rooted to the spot.
Atalanta regrouped and Stendardo proved his worth to the Atalanta team by cutting out dangerous runs from Ibarbo and Sau.
In the 57th minute the centre-back made his strength count at the other end, rising highest to head home an Atalanta corner.
With the scores level Cagliari took the initiative and looked the brighter side for much of the second half.
After a series of half-chances came to nothing, the Sardinians were handed an advantage when Giorgi received his marching orders 10 minutes from time.
The on-loan Novara midfielder, making his home debut, paid the price for his overly combative attitude by picking up his second yellow card inside 13 minutes.
An encouraged Cagliari side nearly settled the contest in spectacular fashion but Conti's acrobatic overhead kick cleared the bar.
