Morata scores against his former club
Ronaldo levels with his 54th goal of season
Tevez struck his seventh CL goal of season
Return leg in Madrid on 13 May
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'Viva Ronaldo!' sing the away fans but it's his former Manchester United team mate Carlos Tevez who looks more likely now. First he takes advantage of a slack touch from Sergio Ramos to shoot wide before Ramos gives it away again and Tevez shoots wide.
Ramos playing like a centre-half in midfield. Luka Modric he ain't...
Former Manchester United defender Phil Neville
BBC Radio 5 live
"Real Madrid are getting overwhelmed in midfield at the moment. If Juventus really go for it now there could be three or four goals for them. Real just seem to be relying on a moment of brilliance from Cristiano Ronaldo or Gareth Bale."
Reiss, Glasgow: Deserved lead for Juventus. However, I wouldn't be surprised to see a Real penalty as from the first corner for Real, strong pulling by Chiellini had already started. Just like when Celtic played Juventus a few years ago.
James from Wokingham: Infuriates me when players don't celebrate against their former teams. Don't worry as much about respecting your old club that got rid of you, and respect the club that you just gave the lead to in the champions league semi final.
Ross in Kent: Why oh why does Ronaldo take free kicks over Bale?! Bale is so much better than Ronaldo at free kicks!
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Image source, ReutersIsco, socks rolled down like Jack Grealish's Spanish cousin, drives forward and hits a shot at Gigi Buffon. Easy save though. Real having more of the ball since the goal.
Former England captain Gary Lineker
BBC Sport
"Electric start from Juve. Real look all at sea at the back."
Kritt Normsaskul: Juve looking the real deal. Brilliant start.
David Smith: Juve look awesome.. pulling Real Madrid apart.
Afolabi Shobowale: Juve looking way stronger than I expected, making Real look very ordinary.
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Real Madrid have conceded as many shots on target (four) in the first 10 minutes as they did in the 180 minutes v Atletico in the last round! Cracking start from the Old Lady.
You've got to celebrate against an old club in a Champions League semi-final haven't you? Biggest goal of your life.
Alvaro Morata scored 10 league goals for Real before leaving last summer. Real come back at Juve now and Toni Kroos tries one from 25 yards, difficult bounce right in front of Gigi Buffon but he turns it away well. Strong wrists.
Former Scotland international Pat Nevin
BBC Radio 5 live at the Juventus Stadium
"Real's players were claiming for offside but the English officials have got that right. The ball that was played in found Carlos Tevez in such a great position - no-one picked him up. Tevez had acres of space, and Alvaro Morata, the pain of trying not to celebrate was etched on his face. He was trying to be cool about it but he must be bursting inside."
Image source, ReutersBefore kick-off, Real Madrid hadn't conceded a goal on the road in Europe for 444 minutes. Juve's start has merited the lead.
Juventus's excellent start bears fruit! Alvaro Morata puts them ahead against his old club and it's more weak keeping from Iker Casillas really. Carlos Tevez bursts into space on the right of the box, he drills in a low shot which is hard and Casillas can only parry it out to Morata, who taps in. Definitely onside.
He doesn't celebrate against his old club. In a semi-final?
Image source, ReutersFormer Scotland international Pat Nevin
BBC Radio 5 live at the Juventus Stadium
"This has been such a lively start. We expected a game of chess but it hasn't been anything like that at all. Everyone wants to go forward. Carlos Tevez and Alvaro Morata have looked really lively up front for Juventus, and there have been some terrible passes to give the ball away, from both sides."
Baz, Manchester: Imagine if Juanfran played for Real and him, Isco and Bale played a quick triangle, the commentary would sound a bit like San Francisco Bay.
Fantastic Baz. Just out of interest, did that thought come to you quickly? Get in touch at #bbcfootball, external, pop on to the BBC Sport Facebook page, external or BBC Sport's Google+ area., external
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Lovely. Alvaro Morata with a lovely first-time lob, a cheeky effort after he saw Iker Casillas off his line. For a moment it looks to be dropping in, Nayim style, but Casillas is able to get back and paw it away.
Eyobel Gomini: Vidal, Marchisio and Pirlo can win the midfield battle v Ramos and Kroos!
Jonny Magrinho: Juventus are the underdogs but I fancy them to win tonight and get Buffon his winners medal. Lethal attack and tight defence.
Vazu: Evra, Tevez, Morata - all previous Champions League winners - can help Juve overcome the giants with their experience in the competition.
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Juve countering with real intent and a PIRLO MISTAKE ALERT! That is a rarity worth capping up. Andrea Pirlo takes too long and Gareth Bale is on him in a flash, nicking the ball away.
Bale and Ronaldo are in on the Juve back four and Leonardo Bonucci has to take one for the team, chops Bale down and is booked. Ronaldo's free-kick hits the wall.
Juventus get through the Real midfield very easily, Toni Kroos with an excuse of a challenge and Stefano Sturaro is able to lash a shot in at Iker Casillas. Nice brisk pace to the game in the opening stages.
Former Scotland international Pat Nevin
BBC Radio 5 live at the Juventus Stadium
"That is a big call, and it takes a brave referee not to give that. There was contact but was it a foul? I think the referee just about gets it right. Arturo Vidal runs into the defender more than he was tackled by him. Terrible touch by Iker Casillas in the build-up."
It looks like Gareth Bale is playing more or less up front with Cristiano Ronaldo for Real. Chance!
Iker Casillas's first touch is a horrible clearance! Juve ping it back up front, Arturo Vidal is on to it but he takes a touch and is closed down.
He wants a penalty but there's no chance of that. Could he have got a shot away?
Casillas looks like Real's weak link every time you see them...
Former Scotland international Pat Nevin
BBC Radio 5 live at the Juventus Stadium
"I hope we get an early goal but I suspect we won't because it's going to be be tactical and technical. Will Gareth Bale and Cristiano Ronaldo get the chance to run at the two Juventus central defenders? If they do then those two battles will be worth watching alone."