"We're very happy to be the first team to win the Champions League in two consecutive years", said Ronaldo, who has now scored exactly 600 goals for club and country in his extraordinary career.
"I'm very happy. It was an unbelievable season again".
"The first half was hard, but in the second we were quickly superior".
Real's victory saw them become European champions for a record 12th time as Zinedine Zidane's side became the first club to retain the trophy in the Champions League era.
"It's a tremendous joy for the players and for this huge club", Zidane told beIN Sports Spain. "This club is the biggest in Champions League history ever, it's great to be a part of and we want to win more".
With a third Champions League title in four seasons secured, having dethroned Barca for their first La Liga silverware since 2012, there were wild celebrations in Madrid.
Juve had been bidding to complete a Treble of Serie A, Coppa Italia and Champions League successes and Allegri said they could still reflect on their season with pride.
The Italians were hampered in the closing minutes when one of their players, Juan Cuadrado, was sent off after being handed two yellow cards.More news: Warren Gatland wants X-factor as Lions bite back at critics
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"We won the (Spanish) league on the very last day". It's the sort of lid chop that says, "come and get me Messi" but also "I didn't have the balls to go full buzz". "I told the players to keep what they were doing but to play wider and put more pressure on them, and I said that when we got the ball play as you know how", Zidane said.
Following an elaborate pre-match ceremony involving American pop act Black Eyed Peas at the Principality Stadium, Juve settled first.
Navas needed to be sharp again in the 6th minute to repel a low shot from Miralem Pjanic.
Ronaldo swept Dani Carvajal's centre into the bottom corner to give the Spaniards the lead after 20 minutes.
Reacting to the defeat, Buffon who has now lost three Champions League finals with Juventus (2003, 2015, 2017), admitted that Madrid were the better team.
Ronaldo's effort was eclipsed seven minutes later by one of the all-time great final goals.