His Finnish rival made a great start and was on the verge of going up a break in the second set before Alcaraz was able to turn it around.
The Spanish teenager, who turns 20 next week, saved five break points in what turned out to be a critical game to remain level at 3-3 in the second set. In the next game, Alcaraz secured his first break to turn the second-round match in his favor.
Alcaraz, ranked No. 2, arrived from successfully defending his Barcelona Open title last weekend and with a chance to move closer to reclaiming the top spot in the world ranking from Novak Djokovic who, like Rafael Nadal, is out with injury.
Ruusuvuori beat Alcaraz on the hard court of Miami in 2021. Alcaraz won that tournament in Florida a year later before also conquering Barcelona and Madrid during a remarkable season that culminated in his U.S. Open victory.
But Ruusuvuori was not expected to give Alcaraz such a tough test on the Madrid clay with the local fans backing their new idol.
The result was still in doubt until Ruusuvuori sent his backhand into the net and ceded his first service game of the third set. Alcaraz clenched his fist, shouted “Vamos!” (Let’s go!) and poured it on to increase his advantage.