It's advantage Inter after Jose Mourinho defeated his old side Chelsea 2-1 in a gripping Champions League last 16 first leg at San Siro.
Esteban Cambiasso scored the winner after Salomon Kalou had equalised Diego Milito's early opener to leave everything open for the second leg in London. But the game may be overshadowed by a serious-looking injury to goalkeeper Petr Cech.
The big team news prior to kick-off was the decision by Chelsea coach Carlo Ancelotti to play Florent Malouda at left-back in the absence of the injured Ashley Cole and Yury Zhirkov. There were no other major surprises as Didier Drogba led the line supported by Salomon Kalou and Nicolas Anelka.
For Inter, Samuel Eto'o got the nod over Goran Pandev to partner Diego Milito in attack. Thiago Motta and Dejan Stankovic returned as starters in midfield, while Julio Cesar was fit to play, sporting two black eyes.
It took Inter just two minutes to break the deadlock. Motta and Wesley Sneijder combined before Milito cut inside John Terry and buried the ball past Petr Cech at his near post.
Chelsea were slow out of the blocks and it wasn't until the 11th minute that they put a decent attack together as Kalou tested Julio Cesar.
The Premier League leaders were desperately unlucky not to equalise on the quarter-hour as Drogba smashed an unstoppable 25-yard free kick against the underside of the bar.
Chelsea started to threaten more and more. Julio Cesar beat the ball away from Ballack, while Drogba spun and fired wide from 10 yards.
The Ivorian was looking dangerous, and he volleyed wide from the edge of the area. Down the other end, Milito was booked for simulation.
On 33 minutes it should have been 2-0 as Eto'o missed an absolute sitter. Sneijder squared the ball across the six yard box, and with it seemingly impossible to miss, Eto'o missed scuffed his kick horribly.
Inter squandered another fine opening soon after. Maicon played a great one-two with Milito, but his touch was heavy as he bore down on goal.
Right on half-time there was a huge penalty shout as Kalou ran through on goal and went down under pressure from Walter Samuel. The referee waved away the appeals, but replays appeared to show that the Argentine had caught the Ivorian's right foot in what would have resulted in a penalty and red card for Samuel.
Chelsea came out of the second half with intent and within five minutes they levelled the scores after a bad goalkeeping error from Julio Cesar. Kalou curled the ball towards the corner, but Julio Cesar let the ball bounce through and over his fingers.
Inter's reaction was immediate and emphatic. Esteban Cambiasso made a rare foray forward, and slammed home the ball into the bottom corner from 25 yards after his original shot had been blocked.
Mourinho went for the jugular and brought on Mario Balotelli for Motta. Meanwhile, Chelsea lost Cech to a serious-looking injury and Henrique Hilario was summoned.
On 65 minutes Chelsea should have equalised again as Julio Cesar saved from Frank Lampard from point blank range after good work from Anelka.
Pandev replaced Eto'o, and Ivanovic made a key tackle on Cambiasso in the penalty box.
Chelsea threw on Daniel Sturridge and pressed for a second goal but Inter held on relatively comfortably for a 2-1 win. There is everything to play for in the second leg at Stamford Bridge.