Atletico Madrid coach Diego Simeone admits his side are not yet comfortable despite a 2-1 win at Reus Deportiu in the Copa del Rey.
Simeone's men fell behind to the Segunda B leaders before goals from Luciano Vietto and Saul Niguez saw them to their away win in the first leg of the last-32 tie.
"They're a competitive team, they use the ball well, have good organisation. I speak well of them. They didn't get desperate, they had good rhythm in the match," Simeone said.
"It was a competitive game, you saw that in the play and in the result. I saw a very strong team on the pitch.
"The tie is tight, it's not a comfortable result."
It was Angel Correa's performance that pleased Simeone, however, and the coach can see the 20-year-old's potential.
"We speak in general, he was quite good in the game, he had commitment, effort," he said.
"He's exciting. Once he takes better decisions in the attacking area, his level will rise massively."
