Napoli have won seven of their last eight league matches and are two points better off than Milan, who beat champions Juventus in midweek to maintain their European push.
Napoli have already ensured that 2019-20, a season that appeared to only be heading one way pre-Christmas, will go down in their history after winning the Coppa Italia last month.
Gli Azzurri have pushed on from that triumph, which assures them of a place in next season's Europa League, by taking 12 points from the last 15 on offer in the league.
Losing 2-0 to Atalanta BC last week all but killed off their top-four hopes, but they have seen off Hellas Verona, SPAL, Roma and Genoa either side of that setback.
With a 15-point gap to make up on the top four, and only seven games to go, Gennaro Gattuso's men are now battling with Roma - with whom they are level on points - for fifth place.
Milan could yet finish fifth, though, as they are now just two points behind Napoli and Roma thanks to an impressive run of form since returning to league action in June.
That run includes an incredible 4-2 win over leaders Juventus, with the Rossoneri recovering from two goals down early in the second half to claim all three points.
Zlatan Ibrahimovic was on target for the fifth time since returning to the club in January, the Swedish striker's arrival coinciding with Milan's upturn in form.
Milan are not assured of a Europa League spot just yet, though, as Sassuolo and Hellas Verona are six points behind ahead of the final run-in.
Extending that gap will be tough this weekend given that Milan have lost their last three games at Stadio San Paolo, while overall they are winless in this fixture since 2014.
Napoli's Serie A form: WWWLWW
Napoli's form (all competitions): WWWLWW
AC Milan's Serie A form: LWWDWW
AC Milan's form (all competitions): DWWDWW
Lorenzo Insigne seems certain to start in attack and he boasts a return of six goals in 14 league meetings with Milan - more than he has managed against any other side.
In terms of the visitors, Hakan Calhanoglu - key to Milan's upturn in form - was not fit enough to start against Juventus but should play a full part here.
Ante Rebic has been a huge hit through the middle over the last month, but Pioli must decide whether to leave the Croatian out here or partner him with Ibrahimovic again.
Indeed, Rebic is the first Milan player to score 10 goals in the second half of a league season since Carlos Bacca in 2015-16.
Napoli possible starting lineup:
Meret; Lorenzo, Maksimovic, Koulibaly, Rui; Ruiz, Demme, Zielinski; Callejon, Mertens, Insigne
AC Milan possible starting lineup:
Donnarumma; Conti, Kjaer, Romagnoli, Hernandez; Saelemaekers, Kessie, Bennacer, Bonaventura; Calhanoglu; Ibrahimovic
We say: Napoli 1-0 AC Milan
Milan have been in great form since returning to action and further enhanced their top-seven credentials with their midweek victory against Juventus. However, Napoli also enter this match on a high and are unbeaten in their last 10 meetings with the Rossoneri, so we are backing them to edge this match.