The two Lombardy clubs come from different stratospheres in terms of history, but only five places separate them in the Serie A standings due to the champions' recent wobble and their hosts' fine start to 2023.
Match preview
Following a seven-game winless run which included two defeats to arch-rivals Inter, Milan may have been unconvincing but ultimately returned to winning ways with a 1-0 victory over Torino last Friday, before quickly turning their attention to matters in the Champions League.
For too long absent from the latter stages of Europe's top competition, the Rossoneri returned to the knockout phase for the first time in nine years by edging a close encounter at San Siro on Tuesday, when they took a one-goal lead against last-16 opponents Tottenham Hotspur and set up an intriguing second leg in London next month.
Having also been eliminated from the Coppa Italia during a January to forget, though, Stefano Pioli's side remain 18 points adrift of league leaders Napoli, and without a hope of defending their Scudetto. In fact, it could be quite a scramble to finish in the top four after recent results dropped them down to fifth.
Switching to a three-man defence at least seems to have stemmed a series of defensive lapses, and with back-to-back shutouts to boast from their past two games, they could now keep consecutive clean sheets in Serie A for the first time since August.
One of five teams realistically in the race to join Napoli inside the final top four, Milan must surely address some woeful away form if they are to pip the likes of Lazio, Roma and Atalanta to the post in that regard.
They have lost their last two away matches without scoring and, this weekend, are in danger of losing three in a row for the first time since 2017. After four straight fixtures at San Siro, the champions now return to the road for what could be a particularly tough test - but at least they will not have to travel far.
In a region rich with top-flight teams at the moment, Monza are threatening to upset the established order in Lombardy, having recovered from a sluggish start to the season to become one of Italy's most in-form teams since the winter break.
Following two defeats against regional rivals at the start of their first year in Serie A - including a 4-1 defeat to Milan - the Biancorossi's subsequent revival has featured an impressive draw with Inter and last month's 3-2 win at Cremonese.
Architects of Monza's rise, former Milan owners Silvio Berlusconi and Adriano Galliani will now see their current club welcome the Scudetto-holders to Stadio Brianteo on Saturday, and they can have every hope of witnessing a historic victory for the hosts.
After following up a second win over Juventus by beating Bologna 1-0 last weekend, when Guilio Donati marked his return from injury with the winner, Monza are on the longest run without defeat in Serie A - some eight games.
Since rookie coach Raffalele Palladino took charge in mid-September, they have gained 28 points from 16 games, with only Napoli, Juventus and Inter picking up more during the same period. Indeed, that tally represents one more than Milan.
Home form has certainly played its part in their ascent to 10th place, as Monza are unbeaten in seven of their last eight league matches at the Brianteo - though they have drawn each of their last three.
Monza Serie A form:
D
W
D
W
D
W
Monza form (all competitions):
W
L
D
W
D
W
AC Milan Serie A form:
D
D
L
L
L
W
AC Milan form (all competitions):
L
L
L
L
W
W
Team News
Though Stefano Pioli will still be without both first-choice goalkeeper Mike Maignan and Alessandro Florenzi, Milan's long injury list continues to shorten, as Fikayo Tomori returns to the squad on Saturday.
Ismael Bennacer could also be available to feature at some stage, but would join recent returnee Zlatan Ibrahimovic on the bench at best. Therefore, Sandro Tonali should again be joined by Rade Krunic in central midfield.
Brahim Diaz struck the Rossoneri's winner in midweek, and the only top-flight brace of his career came in October's reverse fixture - those were also his last goals in Serie A. He should start in support of Olivier Giroud as part of Pioli's new-look 3-4-3 formation; just one of the latter's seven league goals this season have come away from home.
Meanwhile, Monza striker Andrea Petagna has scored and then provided an assist in his last two outings, so should be retained in a settled home side.
Captain Matteo Pessina - who spent time in Milan's primavera but never played for the first team - has had a hand in five league goals since signing from Atalanta last summer and will start in midfield.
With a virtually empty treatment room, wing-back Carlos Augusto could be the only player to miss out for the hosts - particularly as his indirect replacement Giulio Donati scored the winner at Dall'Ara last week.
Monza possible starting lineup:
Di Gregorio; Izzo, Mari, Caldirola; Donati, Pessina, Rovella, Ciurria; Caprari, Mota; Petagna
AC Milan possible starting lineup:
Tatarusanu; Kalulu, Kjaer, Thiaw; Saelemaekers, Tonali, Krunic, Hernandez; Diaz, Giroud, Leao