Real Madrid manager Rafael Benitez will need to wait for a proper assessment of the calf injury sustained by Gareth Bale against Shakhtar Donetsk, but offered positive news on Raphael Varane and Sergio Ramos.

Bale went down clutching his left calf inside half an hour of Tuesday's 4-0 win at the Santiago Bernabeu before Karim Benzema and a Cristiano Ronaldo hat-trick ensured maximum points.

Varane was taken off at the interval while Ramos suffered a shoulder knock in the challenge that earned Taras Stepanenko his second yellow card.

"Bale has had a spasm in his calf," Benitez explained after his first European outing as Madrid coach.

"We'll have to wait a few days to know the extent of the injury. He had a similar problem last year so we've got to be a bit more careful."

Madrid faces Granada on Sunday (AEST) before further La Liga clashes with Athletic Bilbao and Malaga, with Benitez hopeful Varane and Ramos will be able to feature.

"The Ramos and Varane injuries are just knocks, Gareth is the only one that is a bit more negative in terms of the time out," added Benitez.

"We'll have to wait and talk with the doctors to see what happens.

"It was a difficult game as they have talented and dangerous players. This was far from easy, but we have real power up front, we created many chances and we didn't concede any goals.

"The negative thing was the three injuries."