Inter have improved under the leadership of Claudio Ranieri since their poor start to the season.
Reasons to be happy on and off the field for Inter Milan
The great football rivalry in the capital of Lombardy is referred to in a number of ways. The phrase Derby de la Madonnina still gets used, if a little quaintly. Mostly, AC Milan versus Inter Milan is simply the Milan derby.
But over the last few days, the phrase "Market Derby" has also gained a currency, at least in the Italian media. It refers to the bidding war between these two clubs.
In fact, the "Market Derby" has at times seemed far more important than what might actually transpire on the pitch tomorrow night.
At one point, it looked very possible that one Carlos Tevez, disgruntled and out of favour at Manchester City, might even be participating at San Siro. The so-called Market Derby was all about whether, if so, he would be wearing red-and-black stripes or blue-and-black ones.
Milan thought they had all but sealed their longer-running pursuit of the Argentine on Thursday, but their plans were rebuffed by City, who want a permanent sale rather than a loan deal for Tevez. City also want a price closer to €25 million (Dh116.5m) than €20m.
Inter, who became interested in a possible Tevez deal last month, had always seemed slightly behind the pace in this chase, but now look like darker horses. Inter did sound smug when Milan's talks with City collapsed, sensing that disappointment in the Market Derby might just affect morale in the real one.
Other aspects of the timing have also suited Inter ahead of tomorrow's collision.
Had their first Serie A meeting of 2011-12 with the defending champions taken place towards the beginning of the season rather than the beginning of this new calendar year, they would have approached it with dread and from a lowly position in the standings.
As it is, there is now genuine distance between this Nerazzurri, a side coming off five successive league wins, and the shambles of last August and September, when Gian Piero Gasperini started as coach and was sacked within six weeks.
Milan's defence of their title was also a little iffy at the outset but they were in good enough shape to have defeated Inter in the Italian Super Cup 2-1 last August when the two sides last met.
Credit once again to Inter coach Claudio Ranieri, who replaced Gasperini and has done what he now does best: launching recoveries, just as he did at Parma, Juventus and Roma.
Ranieri has kept a wise distance from the Tevez speculation and is not exactly in a position to go storming into the boardroom demanding more strikers.
He has a genuine selection dilemma for the game. Diego Milito looks to have re-found his form; he had two goals in the 5-0 victory over Parma last weekend. And Diego Forlan and Wesley Sneijder have both reported fit after spells out of action.
That is already a crowd to squeeze into the attacking positions; plus there's Giampaolo Pazzini, the striker Ranieri has shown most persistence with, and Ricky Alvarez, the Argentine prospect who looks more and more comfortable playing just off the main forward.
Indeed, for the first time in his four months in charge, Ranieri has a full-strength cast to select from.
That's nice timing, too. "These are special games to prepare for," Ranieri said, "and we are up against a side that has imagination and pace. But we'll be ready for that."