Bruno Cesar had given Sporting a surprise lead in the 47th minute of the game on Wednesday night. And the club, which saw Ronaldo born as a player, was on the verge of a famous victory when their favourite son, playing in his 350th match for the Spanish giants, curled a free kick in to level the scores, reports Xinhua.
Morata, who had come into the game as a 67th minute substitute then gave Madrid all three points with a powerful header from a James Rodriguez cross in the 90+ minute to get Madrid's title defense off to a winning start.
Kiko Casilla remained in goal for Real Madrid, while Rafael Varene replaced Pepe in defense and Karim Benzema was back to form an attacking trio alongside Gareth Bale and Ronaldo.
The visitors almost got off to a flying start in the second minute as Bruno fired just wide and Casillas was soon into action with a save from Bas Dost.
Sporting were looking to sit back and play on the break and Real Madrid were moving the ball too slowly to create clear chances. And it wasn't until the half hour that Ronaldo made his first contribution with a swerving shot that was well tipped over by Rui Patricio.
Madrid looked flat and it wasn't a huge surprise when Bruno put the visitors ahead after half-time with a shot from the edge of the penalty area.
Later, Real Madrid went on to carve out a string of chances and in the final ten minutes it was very much a case of one-way traffic.
In their quest to get back on terms, the Whites were failing to get the rub of the green. Lucas V?zquez shaped in a cross on 83 minutes and just when the home faithful were on their feet to celebrate the equaliser, Ronaldo's left-footed strike crashed off the woodwork.
A minute later, Carvajal once again tried his luck, after James floated in a fine cross and the academy graduate arrived late on the scene to hit the ball on the volley, but his effort flew just wide of the target.
Sporting then held on bravely with some solid defending till Ronaldo's equaliser. Ronaldo produced a sumptuous free-kick from the edge of the area, and despite the diving Patricio getting a hand to the ball, he couldn't prevent the effort from ending up in his net.
With the game now into injury time, James brought the ball under control, lifted his head up and sent in an inch-perfect cross and there was Morata to power home a towering header to secure victory for the Whites.
After the match Ronaldo, who scored 367th goal for Real Madrid, said: "We were a bit flat at the start, but such is football and such is Real Madrid and the comebacks are part of this mythical stadium."
"It was an important goal just as the game was about to finish. I wasn't surprised by the Sporting performance, they wanted to put on a good display and make life difficult for us.
"I hope to always be able to offer something at Real Madrid with good performances and goals. I always want to help out."
