And despite the Frenchman needing five stitches to close the gaping wound, he played the full 90 minutes and even scored.
His agent, Karim Djaziri, claims the horrific cut was sustained in the tenth minute due to a stamp from a Rayo player, and Benzema played the following 80 minutes with pain.
Djaziri tweeted: "Yesterday @Benzema after 10 minutes an opponent stamps on his foot, but as usual he says nothing, plays the whole game in pain, even manages to score!
"At the end the doc gave him five stitches in the locker room."
The match finished 2-1 to Real at the Bernabeu, with Benzema's 31st-minute opener being cancelled out by Raul de Tomas before Rodrygo bagged a late winner.
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Unfortunately for Benzema, the cut means he is a doubt for Real's penultimate match of the season away to Sevilla as his side look to hold off rivals Atletico Madrid in the fight for second place in LaLiga.
That's no surprise given the gruesome nature of Benzema's injury, as shown by his agent's video, which is most certainly not for the squeamish.
His goal in the match made it four seasons out of the last five that the 35-year-old has reached the 30-goal mark in all competitions.
It almost certainly won't be enough to see him pick up back-to-back Ballon d'Ors, but his efforts against Rayo once again show why he's club captain and an icon for supporters.
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Benzema is no stranger to putting football before injury, with his iconic hand strapping due to the long-term need for an operation that would require him to miss game time.