Barca hold a one-point lead over Real and will retain their title with victory at Granada next weekend after thrashing Espanyol 5-0 on Sunday.
However, Real moved up to second place for the first time in 2016 with their 11th consecutive La Liga win, 3-2 over Valencia, whilst Champions League final opponents Atletico Madrid lost 2-1 at already-relegated Levante.
And victory at Deportivo la Coruna next weekend allied to a Barca slip-up will hand Madrid the title.
“I am always positive. Now we are second, there is one game to go and anything can happen,” said Zidane.
“In football you never know what can happen. We need to be aware of that, give our all until the end and see what happens.
“The first part is our part. It won’t be an easy game and we know that.”
Zidane has masterminded a dramatic turnaround in Real’s fortunes since replacing the sacked Rafael Benitez in January.
Madrid have won 20 of their 25 games since the French legend took charge to progress to just their second Champions League final since Zidane scored the winner as a player in 2002 and push Barca all the way in the title race.
“The objective we had fixed was to get into second and now there is just one match left to try and go top,” he added.
“Granada are safe (from relegation) and will play the match as they have to. The important thing is that we do too.
“We have won 11 in a row and we want to show we’ll continue to search for these two trophies.”