Inter remain on course for a domestic double after a late winner condemned Juventus to a 2-1 defeat in the Coppa Italia quarter-finals.
Juve have been struggling in Serie A since their early exit from the UEFA Champions League and had been looking for a win to ease the growing pressure on coach Ciro Ferrara.
They made an ideal start at the San Siro as Diego's 10th-minute shot squirmed past goalkeeper Francesco Toldo.
Inter, nine points clear at the top of Serie A, responded strongly but their pressure was not rewarded for the remainder of the first half as Juve clung onto their lead.
The hosts deservedly equalised when Lucio prodded in Wesley Sneijder's deflected free-kick midway through the second period.
With the tie drifting towards extra time, Thiago Motta's shot after 89 minutes was parried by Gianluigi Buffon and Mario Balotelli converted the rebound from close range to seal the Nerazzurri's place in the last four.
Jose Mourinho's side will now meet Fiorentina in next month's two-legged semi-finals after the Viola beat holders Lazio 3-2 last week.
Roma play Udinese in the other tie after they battled to 1-0 victories over Catania and AC Milan, respectively, earlier this week.
Wednesday 20 January 2010
Fiorentina 3-2 Lazio
Tuesday 26 January 2010
Roma 1-0 Catania
Wednesday 27 January 2010
Milan 0-1 Udinese
Thursday 28 January 2010
Inter 2-1 Juventus
First Leg: Wednesday 3 February 2010
Inter v Fiorentina (1945)
First Leg: Thursday 4 February 2010
Roma v Udinese (2000)
Second Leg: Tuesday 13 April 2010
Fiorentina v Inter (1945)
Second Leg: Wednesday 21 April 2010
Udinese v Roma (1700)
* All kick-off times listed are UK time (+1 for Italy/CET). Times, dates and fixtures are subject to change.
Coppa Italia Quarter-Final Reviews
[20 Jan 2010] - [26 Jan 2010] - [27 Jan 2010] - [28 Jan 2010]
Source: Sky Sports