Buffon sees red as Ronaldo bails out Real
Champions League: Real Madrid 1 Juventus 3 (Real win 4-3 on aggregate)
Cristiano Ronaldo scored an injury-time penalty to book Real Madrid's place in the Champions League semi-final after losing the second leg 3-1, but winning the tie 4-3 on aggregate.
Juventus had wiped out Real Madrid's three-goal advantage from the first leg with Mario Mandzukic scoring twice before Blaise Matuidi levelled the tie 3-3 after an hour.
But with the tie heading towards extra-time, Madrid were awarded a penalty following Mehdi Benatia's challenge on Lucas.
Gianluigi Buffon was shown a red card by Michael Oliver for protesting the decision leaving Ronaldo to score his 41st goal of the season from the spot past substitute keeper Wojciech Szczesny.
Trailing 3-0, Juventus needed a positive start to get back into the tie and Mandzukic gave the Bianconeri the perfect start heading home Sami Khedira's perfectly lofted cross to the back post with 90 seconds played to make it 1-0 on the night and 3-1 on aggregate.
Gareth Bale came close to restoring his Madrid's three-goal aggregate lead but his shot was saved by Gianluigi Buffon and Bale's follow up back heel found the side netting.
Juventus boss Massimiliano Allegri was forced into a substitution after just 17 minutes replacing Mattia de Sciglio with Stephan Lichtsteiner.
That save proved to be crucial as three minutes, Mandzukic scored with another back post header, this time from Lichtsteiner's cross from the right.
With half an hour to play, Juventus had wiped out Real Madrid's three-goal advantage. Keylor Navas failed to collect a cross into the box and Blaise Matuidi was in the right place at the right time to poke the ball home for an improbable equalizer.
Ronaldo then played a pivotal role in the conclusion to the game.
It was his header that Lucas was about to control when Benatia was adjudged to have fouled the Madrid man six yards from goal.
Buffon took his protests too far and was sent off by the English referee before Ronaldo showed great composure to fire his penalty past Szczesny to send the defending champions through to the semi-finals.