There are local derbies, national derbies and everything in between. And then there are "derbies" such as AC Milan v Juventus that barely constitute a rivalry... until game day.
In fact, 363 league days a year, the Rossoneri and the Old Lady have a bit of a love affair. The clubs work together on marketing projects, have made dozens of transfer deals and are generally united in a big way: shared hatred of Inter Milan. Before understanding the Milan v Juve rivalry, one must understand this.
Though the clubs each have an adversarial rivalry with Inter, events during the first decade of the century heightened the shared animosity, actually bringing Juve and Milan closer together on those 363 days a year.
Until the Nerazzurri passed their San Siro mates with a fifth straight Scudetto in 2010, Milan and Juventus stood for eons as the two winningest sides in Italy.
The tide really turned against Inter after the Calciopoli scandal of 2006, which involved fixing of the Serie A referee schedule to massage certain results. AC Milan were relegated to Serie B and docked 38 points over two seasons.
The Bianconeri were hit harder, suffering relegation, having their 2006 title stripped and Champions League invite revoked, plus point deductions and massive fines.
Inter, meanwhile, scooped up the 2005 crown with their two rivals out of the way and escaped punishment completely, despite plenty of reports they had also been involved.
Even with the teams becoming closer through hatred of Inter, all the love and friendship goes out the window those two league days a year when AC Milan and Juventus meet.
The clubs first monster showdown happened in 1901, when both were less than five years old. Milan topped Juventus for a wild 3-2 win in the league semifinal before beating Genoa in the final to win their first Italian title.
From 1930-1935, Milan struggled mightily as Juventus became the first Italian club to ring up five consecutive championships. After World War II, each continued winning crowns, neither ever playing more than eight seasons without one.
Oddly, they have only met once in Europe, that time being the 2003 Champions League final. The match remained scoreless into extras, with Antonio Conte hitting the frame for Juve and Andrea Pirlo following suit for Milan.
In the penalty shootout, Dida controversially crept off his line early in stopping three spot kicks and Andriy Shevchenko settled matters in Milan's favor on the last kick of round five.
They've also faced off in three Coppa Italia finals. In 1942, Juventus busted open a deadlocked tie by winning 4-1 in the Delle Alpi climax. In 1973, Milan claimed a one-off final in Rome on Penalties.
In 1990, the two dueled in an epic two-leg final. After ending scoreless in the Milan opener, Juventus won the trophy on a lone goal just before halftime from Roberto Galia.
As noted, the list of players who have played for both teams is long and star-filled. Players like Roberto Baggio and Pippo Inzaghi moved directly from one to the other, while the likes of Edgar Davids, Zlatan Ibrahimovic and Gianluca Zambrotta have worn both shirts.
Though a relationship based on respect, the curtain of civility certainly comes down on game days. The fan chants get rude, the flares light up and the teams play hard matches.
And even though, they aren't taking part in the textbook definition of a derby, AC Milan executive Adriano Galliani believes the match-up with Juventus is Italy's showcase showdown.
“Numbers clearly say it,” he once told La Gazzetta dello Sport, rationalizing AC Milan v Juventus status as the truest sporting rivalry in the country. “Juve are the side who have won more Scudetti, while we have claimed more titles overall.”
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