In the press conference after the match, one expectant journalist asked if it was Madrid's best performance of the season, AFP reported.
"No I don't think so," Zidane said.
Another suggested this was at least Real’s most complete showing so far.
"There are people who will think it's our best game," Zidane said.
"Not for me, but we have to be happy."
A third finally questioned which matches Zidane preferred, to which the Frenchman proposed the season's opening win over Celta Vigo or last week's 1-0 victory over Galatasaray in the Champions League.
The fact is there are few candidates, from a campaign in which Real Madrid has produced only in spurts, flitting between commanding and chaotic even within individual matches, let alone from week-to-week.
Madrid’s win over Leganes was its most emphatic in the league since it beat Celta 6-0 under Zidane in May 2018 and there have also been resilient away victories at Galatasaray and Sevilla this term, not to mention goal flurries against Granada and Levante.
But both Granada and Levante almost pulled off comebacks while miserable defeats away at promoted Mallorca and Paris Saint-Germain exposed a bluntness up front and fragility at the back that felt all-too familiar.
"The problem is we have to show every three days that we are good," Zidane said earlier this month.
"That is the difficulty and that is what we do not do."
After 10 games, the juncture when teams can supposedly be judged, the picture is still not clear, yet there are signs, in Zidane's selection at least, that his second tenure is taking shape.
A spine has been established with the places of Thibaut Courtois, Sergio Ramos, Raphael Varane, Toni Kroos and Karim Benzema seemingly assured.
Dani Carvajal has been more reliable at right-back than the erratic Alvaro Odriozola while on the other side Ferland Mendy has yet to dislodge Marcelo, despite his 50 million arrival last summer.
Casemiro remains the squad's only defensive midfielder and Fede Valverde has brought much-needed energy into the midfield, leaving the 34-year-old Luka Modric to be used more sparingly.
Up front, Eden Hazard is still not at his best but enjoys a connection with Benzema. If Gareth Bale's fitness or future makes him unpickable, Rodrygo is an exciting alternative on the right, the 18-year-old's pace adding an extra dimension Madrid has so lacked in attack.
"He has character," Zidane said.
"And he is getting better and better."
Zidane's Madrid now has a base but with Real Betis to come at home on Saturday it remains to be seen whether it can be consistent enough to keep up with Barcelona, which has won seven games on the bounce ahead of its match away at Levante.
Lionel Messi's mesmeric performance against Real Valladolid served as an announcement that he is fit and firing again, meaning Barca's title rival may no longer be afforded so much room for slipups.
"We have to look forward," said coach Ernesto Valverde on Tuesday. "What happens is you see Messi playing like that and it seems that it's easy, but it's not easy at all.”
Diego Simeone insists Atletico Madrid is a work in progress but its draw away at Alaves in midweek leaves it playing catchup, with a tough trip to Sevilla on Saturday to come.
Granada and Real Sociedad, the league's two surprise high-fliers, meet at Los Carmenes on Sunday.