Atalanta suffered a shock home defeat and made costly defensive errors, as Sampdoria ended their run of three consecutive losses.
This fixture was originally set for March 4, but was rescheduled after the sudden death of Fiorentina captain Davide Astori.
The hosts were on a roll of three wins in their last four Serie A games, keeping three clean sheets and scoring eight goals. On the other hand, the Blucerchiati were struggling badly and their European hopes evaporating fast, losing three in a row to Crotone, Chievo and Inter with 11 goals conceded.
Josip Ilicic and Leonardo Spinazzola were injured, while Samp missed Dawid Kownacki, Edgar Barreto and suspended Lucas Torreira, plus Fabio Quagliarella not 100 per cent fit.
Atalanta missed a sitter on 14 minutes, as Timothy Castagne pounced on Andersen’s error, but only hit the side-netting when one-on-one with the goalkeeper.
Andrea Petagna was unlucky not to score for the second game running when he got his head to a Papu Gomez corner and it cracked against the crossbar.
Samp’s injury crisis intensified just before half-time when Ricky Alvarez had a knock to the head and had to make way for Gaston Ramirez.
Yet Sampdoria took the lead against the run of play, as Rafael Toloi was caught napping in possession and Gianluca Caprari pinched it to drill in relatively undisturbed.
Substitute Ramirez almost made it 2-0 in stoppages with a magnificent free kick that dipped and swerved towards the near top corner, but Etrit Berisha flew for a remarkable fingertip save.
Atalanta came out fighting for the second half, Bryan Cristante and Petagna shots charged down, but Caprari was dangerous on the counter to turn wide when off balance.
Ramirez tried to curl directly in from the corner flag, finding Berisha’s gloves, but Atalanta were deservedly back on level terms when Gomez’s free kick was knocked down by Barrow for Toloi to fire in from 11 yards, making up for his error on the Samp goal.
Within 60 seconds, Duvan Zapata got his head to a Dennis Praet cross from the right and forced a stunning fingertip save out of Berisha. The Colombian was only later flagged offside.
Barrow made a big difference to the Atalanta attack and Samp needed a desperate clearance to stop him tapping in Petagna’s back-heel flick from close range.
It was suddenly wide open as both teams went at it full pelt in search of the winner. Haas practically cleared off the line as a corner was flicked on by Vasco Regini for Caprari, but a few minutes later Caprari found the woodwork with his header.
Atalanta shot themselves in the foot yet again with a shocking Haas back-pass that surprised Andrea Masiello, so Duvan Zapata kept his cool to thread it beyond on-rushing Berisha.
Deep into stoppages, Andreas Cornelius knocked down a cross for Toloi, who mis-kicked the chance to equalise.
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