In late 2012, he recorded his first live tournament score, a $42,399 victory. The following year, he won the World Series of Poker Europe (WSOPE) Main Event to claim the $1,351,661 first-place prize and a first bracelet at just 19 years old.
Over the next 13 years, he added five more bracelets to his resume – along with more than $70M in cashes – to become widely regarded as one of, if not the, best no-limit hold'em tournament players in the world.
Mateos' climb to the highest level wasn't as smooth as his results suggest. Along the way, he faced his fair share of adversity.
'I thought poker was easy'
In a recent appearance on the Raise Your Edge Podcast, the Spaniard told host Benjamin 'bencb' Rolle that his sustained success at the pinnacle of poker came with its own learning curve.
"In 2017, I was GPI #1 and after that I relaxed myself a little bit because I won too much," he began. "Then I had the biggest downswing I've ever had... I stopped studying. I had a big bankroll at the time and I thought poker was easy. I learned a really important lesson: if you want to keep playing the highest stakes, you need to keep working to maintain your position on the mountain."
In October, Adrian Mateos added a Purple Jacket series win at the Poker Masters to his tournament resume.
Mateos' struggles on the felt were amplified by financial mistakes made off it.
"I was really stressed during this downswing, mostly because of outside problems," Mateos admitted later in the conversation. "It was mentally hard, I remember having one or two years that were really tough mentally."
For many players, the toll of a sustained downswing combined with external pressures would be enough to consider walking away from the game. For Mateos, that was never a possibility.
"Quitting poker was never an option because I still loved to play... I was losing because I was staking many players and investing my money in bad businesses," Mateos went on. "The downswing came more in that way than by playing so I never lost that motivation for poker."
So, how did he turn things around?
"I decided to change everything," he explained. "I decided to take out of my mind all the different things I was doing and focus only on poker. That's why I only play no-limit hold'em and mostly tournaments because I think being a specialist is the best way for me to win money."
Rather than abandon his passion for the game, Mateos transformed the downswing into a learning experience – doubling down on his commitment to improving through study and limiting the off-the-felt distractions.
In the years since, Mateos has been an unstoppable force in the poker world.
"You aren't Superman," he reflected. "You can't do many things super good and I think it's better to focus on one or two things and do them really well."