Sassuolo travelled to Bergamo looking to get back to winning ways after successive defeats to Napoli and Bologna, and were off the mark on 27 minutes when Domenico Berardi slotted home at the back post. 

But Denis, who has re-signed for Argentinian side Independiente, pulled the hosts level just five minutes later on his second attempt from the penalty spot to secure a share of the points for Edy Reja's hosts. 

Sassuolo remain in seventh place at 14 points behind leaders Napoli, while Atalanta moved up two places to 11th ahead of the remaining weekend fixtures.

Having sat on the bench the past two games, Denis lined up from the start and was given the captain's armband for his final game with the Nerazzurri after a four and a half year stint.

The 34-year-old, who joined Napoli from Independiente in 2008 before moving to Udinese then Atalanta in 2011, made way for new signing Marco Borriello five minutes from the end to prompt a standing ovation at the Atleti Azzurri d'Italia stadium.

Denis shook hands with several players and the match referee before hugging Reja -- the coach of Napoli when he arrived in 2008 -- on the touchlines, where several hoardings in black and blue proclaimed 'Thank You German' and 'German Forever'.

Although the only trophy in Atalanta's cabinet is the Italian Cup from 1963, the Serie A club boast one of the most loyal supports in the league and Denis has legendary status among the Nerazzurri fans. 

He finished his Atalanta career with 56 goals and as the club's top non-Italian goalscorer, a tally which included hat-tricks in games against Roma and Inter Milan.

Roma, in fifth at 12 points off the pace, host Frosinone in Saturday's late fixture looking for their first win in five games and their first under new coach Luciano Spalletti.

Champions Juventus, two points adrift of Napoli in second, can go top of the league for the first time on Sunday with a win at Chievo.

Napoli host Empoli in the afternoon while Inter Milan, in fourth at six points adrift, are away to AC Milan in the city derby while third-placed Fiorentina are away to Genoa.