Beaten Alcaraz not distracted by 'expectations'
The 18-year-old Spaniard, seeded eight, was stunned 7-6 (7/2), 6-7 (5/7), 6-3 by American Sebastian Korda in their second round clash on Wednesday.
Alcaraz had arrived on the back of winning the prestigious Miami Masters title.
However, the world number 11 was outgunned by Korda in a thrilling clay court battle lasting just over three hours.
"I'm a bit disappointed with myself. I had a lot of chances to be up in the match and close to winning, but these losses sometimes good to live. You have to play matches," Alcaraz said.
"But I didn't think about the expectations that the people have for me. I just focused on me and what I have to do. But as I said, you have to play more matches on clay courts."
Alcaraz is the second big name to exit the tournament following world number one Novak Djokovic who also lost his opener on Tuesday. Alcaraz committed 36 unforced errors in Wednesday's defeat.
"It's not easy to get your bearings on clay," he added.
"It was a difficult match, but I feel mentally ready to play these types of matches, long and tight.
"I am ready to return to training and focus on the next tournaments."
Korda -- ranked 42 in the world and like Alcaraz competing at Monte Carlo for the first time -- will play fellow American and Indian Wells champion Taylor Fritz in the next round.
"I'm very comfortable on clay. I grew up on green clay in Florida," said Korda, 21, whose lone career title came on the surface in Parma last year.
"So I know how to play on clay, I move quite well, I feel good there."
Next up is a last-16 clash with Fritz who defeated Marin Cilic 6-3, 4-6, 6-4.