Juventus striker Carlos Tevez smashed home a second-half penalty as the hosts stunned holders Real Madrid with a 2-1 win in an absorbing Champions League semi-final first-leg.
The irrepressible Argentine won the spot kick just before the hour when he was upended by Dani Carvajal on a breakaway and tucked it away to give Juve the edge aften a pulsating, open game.
The home side's Alvaro Morata scored against his old club, although he declined to celebrate, in the ninth minute but Cristiano Ronaldo headed the equaliser for Real in the 27th.
Although Juventus are regarded as one of the most powerful clubs in Europe, Serie A's recent decline means they have been unable to keep up financially with the continent's elite and were regarded as relative lightweights among the semi-finalists.
They were given a painful reminder of the gap two years ago when Bayern Munich beat them 4-0 on aggregate in the quarter-finals but Tuesday's win suggests they are back near the top.
"We made more mistakes than usual, not just Sergio, but at the back we had more difficulies because Juve put us under a lot of pressure but Sergio did a good job as he did in the past games," said Real coach Carlo Ancelotti.
The other semi-final takes place between Barcelona and Bayern Munich.