Napoli’s indifferent form continued as they were held to a goalless draw by relegation-threatened Hellas Verona at Stadio Diego Armando Maradona.
The Serie A leaders are 14 points clear but have now won just one of their past four games in all competitions.
Fit-again top-scorer Victor Osimhen came off the bench and hit the bar but the hosts could not find a winner.
After Lazio won at Spezia on Friday, Napoli need 11 points from eight games to clinch a first title since 1990.
Head coach Luciano Spalletti rested a number of players, including Khvicha Kvaratskhelia, but the winger was summoned from the bench in the second half as the home side struggled to find the breakthrough.
Matteo Politano did have the ball in the net in the first half, but his deflected effort was ruled out due to a Napoli player in an offside position obstructing Verona goalkeeper Lorenzo Montipo.
Osimhen had the best chance of the second half but shot against the woodwork before Cyril Ngonge nearly won it for 18th-placed Verona – but he shot wide after going through on goal.
Elsewhere, AC Milan went behind after just 32 seconds in their 1-1 draw at Bologna.
Milan boss Stefano Pioli made a number of changes ahead of the second leg of their Champions League quarter-final tie with Napoli, but may have regretted his decision when Nicola Sansone put Bologna ahead in the first minute.
Midfielder Tommaso Pobega equalised five minutes before half-time and a point keeps Milan in fourth.
Inter missed the chance to overtake their rivals after they fell to a shock 1-0 defeat at home against Monza.
Former Inter academy player Luca Caldirola scored the winner for the visitors in the 78th minute.
In the dying seconds, Edin Dzeko was unable to get on the end of Lautauro Martinez’s flicked header and Inter remain win less in the league since 5 March.