Thibaut Courtois admitted that Real Madrid were poor in the second half of their uncomfortably close win over La Liga strugglers Huesca on Sunday.
Gareth Bale's early goal was enough to give Santiago Solari's men the three points, but the side which lost 8-2 to Barcelona earlier in the season made life difficult for their prestigious visitors.
"In the first half we played well, we controlled the game and we did things the right way," said the Belgian keeper, quoted by Sport.
"In the second half it was difficult, we had the wind against us and it was difficult to play properly, we did almost nothing in the second half.
"It's good to keep a clean sheet, we have to continue like this."
Courtois' clean sheet was his fifth in his last seven appearances as Real Madrid's improvement under Solari continues.
Solari also cited the blustery conditions, which saw Real playing into a headwind in the second half, as a factor which affected the quality of the match.
"The wind took the beauty out of the game, it was very difficult to control and pass," Solari said. "If you ask the players, we became less precise because of that."
Los Blancos are up to 4th after Sunday's victory although they remain five points behind leaders Barcelona, who won 4-0 at Espanyol on Saturday.