Victory cuts third-placed Real's deficit on Barcelona at the top of La Liga back to eight points.
However, it was another off night for Madrid's strikers as Cristiano Ronaldo and Karim Benzema were held scoreless as Casemiro, Isco and 21-year-old Asensio provided the killer touch.
Benzema has been fiercely criticised for his role as Real lost to promoted Girona last weekend and at Tottenham Hotspur in the Champions League on Wednesday.
Both Ronaldo and Benzema have only one La Liga goal each to their name so far this season and it was the World Player of the Year who had Real's next three efforts as he blasted into the side-netting, curled a shot just wide and then placed a header from close range too close to Lizoain.
Madrid had to wait until four minutes before half-time to break the deadlock when Casemiro grabbed Real's first headed goal of the season from a corner.
The visitors had a penalty shout early in the second- half, but on-loan Atletico Madrid winger Vitolo went to ground too easily despite a slight pull of his shirt by Casemiro.
A booking would have ruled Casemiro out of the Madrid derby against Atletico in two weeks' time and he was quickly replaced after Asensio secured the three points in stunning fashion.
Asensio has made a habit of netting in spectacular fashion in his first 18 months at Madrid and pounced on a loose ball 30 yards from goal to rifle a shot that rose all the way on its trajectory into the top corner.
Elsewhere, Villarreal's unbeaten league run since Javier Calleja took charge in September continued as Nicola Sansone came off the bench to grab both goals in a 2-0 win over Malaga to move the Yellow Submarine up to fifth.
Real Sociedad were also comfortable 3-1 winners over Eibar. However, their Basque rivals Athletic Bilbao's slump show no signs of abating as they conceded three times in the opening 26 minutes to lose 3-1 at Celta Vigo with Iago Aspas netting twice for the hosts.
And Girona moved into the top half of the table by backing up their stunning upset of Real Madrid last weekend by edging out Levante 2-1 in the lunchtime kick-off.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
