Asensio's spectacular 74th-minute strike, firing in from distance for his eighth goal of the season, was enough to give Madrid the win against a well-organised Granada team. The result leaves table-topping Madrid on 53 points, six clear of second-placed Sevilla, who had been held to a draw at Osasuna a day earlier.
"Yes, it was hard for us," coach Carlo Ancelotti said after the match. "We reacted well. The objective was to win today and react. We won, we played a very good second half, we deserved it. It isn't our best moment but I expected this from the team, a good reaction and three points.
"We can't relax. It's good we have a week to work now, and prepare for the upcoming games, that will be interesting."
Visitors Granada started well, and Thibaut Courtois was called into action early on to save from Antonio Puertas. Isco and Asensio combined for the latter to work Granada keeper Luis Maximiano, before Dani Carvajal's delivery from the right was diverted onto the crossbar by defender Carlos Neva.
Rodrygo saw a shot deflected into the side netting and Toni Kroos curled an effort off target as Madrid began to pick up the pace. Maximiano saved from Asensio from distance and from Isco on the volley as Madrid threatened again before half-time, without making the breakthrough.
Camavinga was replaced by Federico Valverde at the break, and the Uruguay midfielder soon found himself through on goal, only for referee Antonio Mateu Lahoz to call play back for a foul. Luka Modric had a shot blocked, Rodrygo twice tested Maximiano and Asensio again went close as the home side continued to increase the pressure.
Ancelotti then brought on Luka Jovic and Eden Hazard, and the pair wasted no time in combining for Jovic to fire just wide. Soon afterwards, Asensio opened the scoring with a thundering long-range shot after a corner routine had broken down.
Madrid were awarded a penalty when Maxime Gonalons brought down Hazard -- only for the spot kick to be changed to a free kick by VAR -- before Asensio was denied a second goal by a superb stop from Maximiano.
"I've been here a long time and there are no easy games," Madrid captain Marcelo said after the match. "Today the game was really difficult, they demanded a lot from the first minute, we had a lot of patience with the ball and in the end we scored, they're three important points.
"It was a strange game to be honest, in the first half we lacked patience. In the end we had that patience and we had more of the ball, more passes and we scored ... [Asensio] has an incredible shot."