Real Madrid talisman Cristiano Ronaldo departed the action deep into stoppage time of Wednesday's win over Villarreal clutching his right hamstring.
The sight will come as a concern for Madrid, who cruised to a 3-0 victory at the Santiago Bernabeu to keep pace with Barcelona and Atletico Madrid in a thrilling La Liga title race.
After holding the back of his right leg, Ronaldo walked from the field and sat on the bench, with Madrid having used all three substitutes.
Any injury to the Portuguese superstar would come as a major blow to Zinedine Zidane's side, who are a point behind Barca and Atletico with four games to go and have a Champions League semi-final to come against Manchester City.
‘After Manchester City’s recent form, maybe they’re the underdogs against Manchester United!’ Former Red Devils defender on this weekend’s derby
‘Arteta, Alonso, Emery, me… none of us were physical players – we needed the understanding of the game. That probably helped us move into management’: Premier League boss reveals reasons for natural career progression
