After six seasons at the Santiago Bernabeu and four Champions League wins, Bale's number appeared to be up over the summer, goal.com reported.
Having barely been taken into account by Zidane toward the end of the 2018-19 the Welshman found himself in the middle of a bitter transfer standoff.
Real's determination to sell its winger was only matched by Bale's refusal to leave unless his lucrative contract terms in Spain were matched elsewhere, leading to an impasse as the transfer window dragged on.
And despite Zidane's assurances that Bale would not be in his plans, he ended preseason in the Madrid first team while a prospective move to China failed to materialize.
Bale started Madrid's Liga opener on Saturday in the absence of the injured Eden Hazard and set up Karim Benzema as the French striker opened the club's account early on against Celta.
Toni Kroos and Lucas Vazquez extended the winning margin before Celta youngster Iker Losada scored off the bench in injury time to mark a final scoreline of 3-1 in the Merengue's favor.
And after the final whistle Zidane had no qualms in assuring Bale he would have a part to play in 2019-20.
"He is going to stay. We have to focus on this season, nothing else," the coach explained to reporters.
"Hazard's injury is bad luck for us, but it has not changed the idea we had for Bale in this game.
"Gareth, James [Rodriguez] and all the players here are going to defend this shirt."
Having finished a distant third behind Barcelona and Atletico Madrid during last season's disastrous league campaign, Madrid now sits three points ahead of its Catalan rival following Friday's defeat at the hands of Athletic.
And Zidane was happy with what he saw from his own men to avoid an opening day slip, despite missing the likes of Hazard and Dani Carvajal and going down to 10 men when Luka Modric saw red.
"I am happy for the players. We played a great game today, above all in the first half. With 10 we played very well, together and defending as a team," he added.
"We were effective. I am happy with what I have seen.
"Starting the season ahead of Barca? We only think of ourselves. The most important thing was to pick up three points at a tough ground. We have to congratulate the players."