Carlos Alcaraz clenched both fists and roared "Vamos! Vamos! Vamos!" at the packed stands of the Madrid Open.

His war cry of "Let's go!" in Spanish draws motivation for Alcaraz when he faces difficulty, and revs up his fans. This time it worked.

The defending champion survived a tougher-than-expected test by 41st-ranked Emil Ruusuvuori in his opening match on Friday.

Alcaraz was on the brink of an early upset before he dug down for a 2-6 6-4 6-2 victory over his Finnish opponent.

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 jokingly apologised to the partisan crowd for the close call.

"It wasn't just a scare for them, it was (a scare) for me, too," Alcaraz said.

"I am just happy I could get this very difficult win. . . . Maybe people think that I should win easily or not get into trouble in matches, but each match is its own world. It was a very hard match. You just have to stay humble and accept the bad moments as they come and try to turn it around."

On the women's side, No. 1 Iga Swiatek eased past Julia Grabher of Austria 6-3 6-2 after the three-time Grand Slam winner converted three of five break chances.

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.

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 poured it on to increase his advantage.

Alcaraz will next face Grigor Dimitrov after he beat Gregoire Barrere 6-0 5-7 6-3.

Also, third-seeded Casper Ruud lost to Italian qualifier Matteo Arnaldi 6-3 6-4.

Fifth-seeded Andrey Rublev advanced after seeing off Stan Wawrinka 7-5 6-4 as the Monte Carlo winner improved to 9-1 on clay this year.

Also in the women's tournament, third-seeded Jessica Pegula, who was a finalist in Madrid last year, got past Polish qualifier Magdalena Frech 7-6 (5) 6-3.