Zinedine Zidane called for improvements in Real Madrid's finishing after his side needed a late Nacho goal to clinch a 1-0 victory over Real Valladolid at Estadio Jose Zorrilla on Sunday.

Nacho connected with a Toni Kroos cross to head Madrid in front after 78 minutes of a tightly contested match to earn Zidane's men a win that moved them three points clear at the top of LaLiga.

Zidane praised his defence after Valladolid failed to register a shot on target but said more creativity is required to ensure struggling opponents are beaten more convincingly.

"Defensively, what we are doing, we are doing well. It is our strength," Zidane told reporters.

"We defend all and when we lose the ball we recover it very high, and if we keep it we have a good chance of scoring.

"Nacho scored and that is part of football. We know that we can improve in this aspect.

"Nacho is a professional. When he has to compete he does well. I'm glad for his goal; he doesn't usually score them but from time-to-time we can also create chances for defenders."

Zidane refused to be drawn on his side's title chances despite opening up a gap over rivals Barcelona, who lost 2-0 to Valencia on Saturday.

Madrid have been beaten only once in the league this season but with 17 games remaining, including the visit of Barcelona on March 1, Zidane predicted a tough road ahead.

"For us, nothing changes," said Zidane. "We are happy with the victory, the work done having fought until the end, but nothing changes. There are 17 games left and we will continue fighting until the end.

"I don't want to talk about being champions because there is still a lot left to play.

"It changes nothing to be leaders, they are three important points but nothing more.

"There are a lot of league games left and it will be difficult for all teams, including us."

Madrid's next game is at home to city rivals Atletico Madrid on Saturday.