Napoli achieved a hard fought 1-0 victory against hosts Atalanta in the 21st round to strengthen their grip over the top spot in the Serie A football league.

Returning to competition after a two-week break, Napoli’s Belgian forward Dries Mertens scored a goal in the 65th minute on, which proved to be decisive on Sunday, reports Efe.

Following their win, Napoli continue to top the Serie A table with 54 points, four ahead of the second-placed Juventus, who are set to take on Genoa on Monday evening.

Lazio crushed Chievo 5-1 to jump to the provisional third spot with 43 points — one ahead of Inter Milan, who host fifth-placed Roma (39 points) later in the evening in Milan.

It was an important win for Napoli, taking revenge for their loss to Atalanta earlier this season in the Italian Cup quarter-finals and two other league defeats in the previous season.

After a goalless first half, Napoli’s Jose Callejon had a scoring chance in the 55th minute, but Atalanta’s Bosnian keeper Etrit Berisha blocked the ball.

Over time, Napoli’s players gained confidence, with Mertens scoring the lone goal after making the most of Callejon’s pass.

This was Mertens’ first goal in nine league matches and 910 minutes.

However, Napoli held firm during the remaining minutes, with their net minder Pepe Reina saving a shot by Bryan Cristante in the 72nd minute.

Marek Hamsik could have doubled Napoli’s tally, but the goal was officially annulled after being ruled offside.

Elsewhere, Fabio Quagliarella scored a hat-trick as hosts Sampdoria downed Fiorentina 3-1 to jump to the sixth spot.

Sassuolo held Torino 1-1 at home as the former jumped to the 14th spot.

Crotone beat Verona 3-0 to move to the 17th position, overtaking SPAL who drew Udinese 1-1.

Bologna defeated bottom-placed Benevento 3-0 to put pressure on 11th-placed Fiorentina. Bologna have 27 points — one less than Fiorentina.