It will be a tense Tuscan reunion when former teammates-turned-coaches Massimiliano Allegri and Luciano Spalletti meet Wednesday (2:45 p.m. ET) in the Champions League.
"It's going to be the match of the year for us," Zenit St. Petersburg coach Spalletti said of the Russian team's chances. "After a loss at Malaga we have definitely complicated our road in the Champions League. Milan is also not at its best moment in history and the result on Wednesday will be the key one for both teams. We will have to show our character to win."
Seven-time champion AC Milan has won only two of seven matches in all competitions, putting Allegri's job on the line. Spalletti is among those being floated as a possible replacement.
Allegri and Spalletti played together 30 years ago with Serie D side Cuoiopelli. Both coaches are from Tuscany, and they were born 50 miles apart, in Livorno and Certaldo, respectively.
Russia coach and former Milan manager Fabio Capello will likely be at the Petrovski stadium to watch his former squad meet many of his current players.
In the other Group C match, Anderlecht hosts Malaga.
Malaga leads the group with three points after beating Zenit 3-0 in its opener. Anderlecht and Milan are next with one each after drawing 0-0.
Anderlecht is seeking its first home win in the Champions League in nine years, and the Belgian side should face a tough test in Malaga, which is unbeaten and in third place in the Spanish league.
Malaga also beat Panathinaikos in the playoffs to reach the group stage. Against Zenit, under-21 Spain midfielder Isco scored twice.
In Serie A, Milan has just two wins in six matches. After giving up the lead in a 1-1 draw at Parma on Saturday, Allegri has come under more pressure.
"Allegri is not up for discussion, but any manager needs to put up results," Milan vice president Adriano Galliani said.
Milan is struggling to overcome the loss of an entire squad's worth of top players, including the likes of Zlatan Ibrahimovic and Thiago Silva, who both bolted for Paris Saint-Germain. Stalwarts Alessandro Nesta, Gennaro Gattuso and Clarence Seedorf also left.
Giampaolo Pazzini scored a hat trick against Bologna a month ago but has been bothered by injuries since then. He could return against Zenit, with the Milan derby four days later.
Another Milan forward, Alexandre Pato, is still working his way back from a thigh injury. The Brazil striker has yet to play this season after getting injured at the end of August.
Meanwhile, Zenit is looking to extend a 16-match home unbeaten streak in Europe, stretching back to a 2-1 loss to Real Madrid in its Champions League home debut four years ago.
The Russian champions have won 10 and drawn one of 11 European home matches under Spalletti.
However, Zenit is only tied for sixth with Rubin Kazan in the Russian league, five points behind leader Anzhi after 10 games.
Zenit midfielder and Russia captain Igor Denisov and forward Aleksandr Kerzhakov have clashed with Spalletti over the big contracts given to newly signed Hulk and Axel Witsel, who were acquired from Portuguese sides FC Porto and Benfica, respectively.
"We've had some problems but Milan is going to find a united squad," said Zenit defender Domenico Criscito, who was exluded from Italy's European Championship team after being placed under investigation for match-fixing.
Criscito scored in Saturday's 1-1 draw with Lokomotiv Moscow but also broke his cheekbone. He flew to Milan for treatment and a protective mask. Also against Lokomotiv, Belgium defender Nicolas Lombaerts broke his nose. Both Criscito and Lombaerts are planning to play against Milan.
And Denisov is still suspended for his salary protests.
Witsel, a highly touted 23-year-old midfielder, is back from an unspecified injury he picked up with Belgium in September.