Karim Benzema and Lucas Vazquez are also expected to be brought back to Real Madrid's attack alongside Cristiano Ronaldo.
A win or a draw in the match postponed from February because of bad weather will move Madrid past Barcelona into first place going into the weekend's final round of matches.
After Nacho Fernandez had given Madrid a controversial 10th-minute lead with a quickly-taken free-kick, Ronaldo reached the milestone with a simple tap-in to make it 2-0 in the 23rd minute.
"Navas has been - and still is - fundamental", Zidane said at a news conference.
The Spanish global and four-time victor of the competition said, via Marca.: "Madrid and Juve are just Champions finalists, but you lose interest when you do not play the final". Everybody is doing very well physically and wishing that the game starts as soon as possible. "He's always there in the decisive moments", he added. It was the ideal goal for the occasion, and epitomised the inhuman goal-scoring instinct of Ronaldo.
Real Madrid will play at the Estadio Municipal de Balaidos having recorded a series of positive results from their previous matches.
Zinedine Zidane's team now need only to avoid defeat in their final match of the season, away to Malaga, to win the league.
"Cristiano will be with us", Zidane said.
Nicola Sturgeon rejects 'ludicrous' claims Tory surge could stop referendum bid
The First Minister also made clear she is confident the SNP will be able to hold on key constituencies the Tories are targeting. The SNP hailed the council elections as a victory after the party won 431 seats, more than any other single party.
With three games to play over the next seven days, Zidane opted for a rotated line-up - a strategy that has allowed him to maintain his players' fitness levels remarkably well throughout the season.
Madrid remain in the driving seat after the European champions saw off Sevilla 4-1 as they have two games remaining to Barca's one.
Besides, Real Madrid already lost the possibility to win La Liga title in 2014, the year Los Blancos won the 10th Champions League in Lisbon.
Artiz Adruriz's close-range strike - his 16th league goal of the season - gave Athletic the lead after 13 minutes.
Madrid have won the past five meetings between the two teams. "He's just got something, he's different". The Catalan club still has a chance of winning its third straight title because of a better head-to-head tiebreaker.
The game was put to bed 12 minutes from time, as Ronaldo scored his 400th goal for Real Madrid.