The club captain hailed his team-mate following his magnificent winner at Granada while describing on-form striker Karim Benzema as "unique"
Modric popped up in the 85th minute and secured maximum points for Madrid after Granada's Youssef El-Arabi cancelled out Karim Benzema's first-half opener.
The goal was Modric's first La Liga goal this season and just his second in all competitions, with Zinedine Zidane calling on the Croatia international to shoot more often afterwards.
And Ramos went on to reiterate his coach's comments, stating the 30-year-old had the potential to deliver match-winning moments and become a key member of the squad.
"His goal today makes him more visible, but for me what he brings to the game is a must," Ramos told Movistar Plus. "He's never marked out much, but he is the backbone of the team."
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Ramos bemoaned his side's lack of killer instinct in front of goal but was relieved it did not cost them two more points as Madrid continued to struggle for fluency away from home.
Madrid trail league leaders Barcelona by four points having played a game more.
"We had chances to kill the game but we didn't and it was difficult for us then," he reflected. "In the end, the team persisted and Luka scored a great goal to give us the three points.
"People have the image of us at the Bernabeu mastering games, pressing up and today there was not much of that, but there are positive conclusions to draw.
"We have to keep getting better."
Ramos was also keen to praise Benzema after he continued his hot-streak in front of goal after scoring 11 goals in nine league games.
"His streak is good for us, he could have scored a second, but still he's a tremendous joy," Ramos said. "At his best he is a unique player."