Lazio's struggles in Serie A this season continued as they returned from Bergamo with a 2-1 defeat to Atalanta.
Luca Cigarini put the hosts in front before the interval, but when Brayan Perea levelled during Lazio's brightest spell of the game, Vladimir Petkovic's men looked favourites to go on and find a winner.
However, it was German Denis who scored next, sealing Atalanta's fourth win of the season and taking them above AC Milan and their hosts into seventh.
Over half an hour of sizing each other up was followed by the first chances of the game, one at either end.
Sergio Floccari had the first for the visitors with his shot taking a deflection on its way wide of the far post in the 33rd minute.
Shortly after, Giacomo Bonaventura's effort was saved well by Federico Marchetti with Maximiliano Moralez in an offside position as he met, and missed, the rebound.
Atalanta took the lead in the 42nd minute with a goal out of nothing.
Cigarini let the ball fall to his right foot before sweeping in a volley from 20 yards which sneaked just inside the post with Marchetti unable to reach it.
Lazio emerged with more attacking intent and they were rewarded when Perea brought them level in the 53rd minute.
He took advantage of some two poor defending from two Atalanta players who simply left the ball for him to tuck in from six yards.
Hernanes saw his free-kick pushed away by Andrea Consigli as Lazio stepped up their search for a winner, Miroslav Klose sent on for the final 10 minutes.
But it was Atalanta who found the winner as Lazio committed too many men forward and left their defence wide open.
Denis broke through and took the ball round Marchetti before scoring into the empty goal to earn the Bergamese side all three points.