With this win, RM becomes the first team in the Champions League history to defend the UCL title.
Zidane, 44, led Madrid to glory in last season's Champions League less than 5 months after succeeding Rafael Benitez to take up his first managerial role.
Bale has not played since injuring a calf muscle in April but managed 13 minutes after coming off the bench and was delighted to win Real's 12th European Cup at his national team's stadium.
After Ronaldo opened the scoring by turning home Real's first shot on goal, Mandzukic scored a sublime overhead kick - surely one of the greatest ever goals ever to grace this stage.
Overwhelmed and unable to focus when the pressure was really ramped up, Juventus suffered more heartbreak in a European final, just when they looked primed for an assault at halftime, with the scores level at 1-1.
"But today we can say that we are a very good team and that we deserved to win the league and the Champions League".
While Ronaldo is the man who applies the killer blow, Modricis the team's strategist, quietly working to create avenues and openings for Madrid to capitalise on. The goalkeeper blocked a header and strike from Gonzalo Higuain, and produced a one-handed save when Miralem Pjanic picked a gap through a crowd of defenders.
Real's Toni Kroos was in awe of his team-mate Ronaldo. The world player of the year knocked the ball across to Dani Carvajal on the right flank before drifting into the penalty area to receive it back and beat Buffon. Tied with five titles each are Bayern Munich, Barcelona and Liverpool.
"It's a tremendous feeling of joy for the players and the club", Zidane added.
However, with Modric's steadying influence increasing, the tide turned in favour of Zinedine Zidane's side and they stormed to victory, firing more goals past Buffon than the three he had conceded in the rest of the tournament.
This was also the night when the formidable BBC - that incredible defensive wall of Leonardo Bonucci, Giorgio Chiellini and 36-year-old Andrea Barzagli - was demolished. Would anyone bet against him doing it all again next year?
"In the second half their class, strength and how accustomed they are to winning these games showed through".