Luis Enrique is wary of the threat posed by Alaves as Barcelona travel to the Mendizorrotza Stadium in La Liga on Saturday.
The two sides will also face each other in the Copa del Rey final on May 27 after both won their two-legged semi-final ties this week.
Alaves have already beaten the defending champions this season, winning the reverse fixture 2-1 at the Nou Camp, and Enrique was full of praise for their opponents ahead of the trip.
"Alaves are the revelation of the season without a doubt, because of what they are achieving and how they are doing it," he told a pre-match press conference.
"Their points total, their consistency, their position in the table….and all of this as a team who have just come up from the second division and have a new coach.
"They are getting some spectacular results playing at a great level in both the league and the cup.
"We know they are a team who have caused us problems and could do so again. Here they did so with a system they haven't used again, with a defensive five but normally they play a 4-2-3-1. We'll see what Mauricio Pellegrino decides tomorrow.
"In spite of the extra day's rest, we are coming off the back of 13 intense games. It isn't an excuse, it's the reality and we will do our best."
Javier Mascherano is not available after sustaining a thigh injury in midweek while Rafinha could return after a broken nose ruled him out of Tuesday's match.
Andres Iniesta and Sergio Busquets returned against Atletico and are in contention again but Gerard Pique and Arda Turan are both out after missing training on Friday.
Alaves' Copa del Rey hero Edgar Mendez, who came off the bench to score the winner against Celta Vigo in midweek, suffered a leg injury and misses out for the hosts.
Alaves boss Pellegrino said: "To beat Barca, the planets will have to align.
"We are up against a team of stars, one of the best in the world and we are going to have to be at our very best to have a chance in the game once more."