Rome - Derby matches have shaped the coaching careers of Simone Inzaghi and Stefano Pioli in the past, but the stakes are higher than ever when the former apprentice and master face off in a crucial Milan meeting on Sunday.

Four points separate leaders Inter from third-placed AC Milan ahead of their San Siro clash, although the champions have a game in hand against Bologna to come.

It is a pivotal moment in the Serie A season, contested by two coaches who know the significance of city rivalries as well as anyone.

In April 2016, then-Lazio coach Pioli suffered a 4-1 defeat by capital rivals AS Roma, a result that cost the manager his job.

One man's crisis was another’s opportunity as Inzaghi, at the time a youth coach with the Roman club, was promoted to guide the first team until the end of the season in Pioli's place.

Lazio's failed move for Marcelo Bielsa ultimately led to Inzaghi being installed as their permanent coach, and his success over the next five years led to his appointment at Inter in the off-season.

Neither coach’s job is at stake on Sunday, but the Serie A title could well be, according to former Milan and Inter striker Christian Vieri.

"If Inter win, Milan will be out of the Scudetto race," the former Italy international told Gazzetta dello Sport.

"With a potential 10-point gap, how could you claw that back against these league leaders? Against a team that is showing that it can also be ruthless when needed?"

For Milan, the weight of recent history must be overcome too as it was almost exactly a year ago that the Rossoneri’s Serie A title bid went off the rails.

A shock defeat by Spezia allowed Inter to overtake them on Week 22 of the 2020-21 campaign, the Nerazzurri moved four points clear with a 3-0 Milan derby victory a week later and they never looked back.

Inter are now in a stronger position than before, but the situation is eerily familiar for Milan.

Before the international break, they lost to Spezia again, and a draw with Juventus left the feeling that anything but a win over Inter could end their involvement in the Scudetto race.

Second-placed Napoli are also firmly in the mix, and travel to relegation-battling Venezia on Sunday.

Milan could be without Zlatan Ibrahimovic, a man for the big occasion, as the Swede recovers from an Achilles tendon problem, while Fikayo Tomori is also doubtful.

Inter follow the derby with games against Roma in the Italian Cup, Napoli in Serie A and Liverpool in the Champions League during a run of six matches in 22 days.

Juventus’s big January signing Dusan Vlahovic is in line to make his debut against Hellas Verona, fourth-placed Atalanta host Cagliari and Roma take on Genoa.