Real Madrid, who was missing eight players due to the outbreak of the Corona virus in the club, extended its unbeaten record to 15 games in all competitions, and reached the middle of the season with 45 points, eight points ahead of Seville and 13 points over Real Betis, third in the standings.
Bilbao remained in tenth place with 24 points.
Benzema broke the 400 goal barrier in his career with an amazing shot from outside the penalty area in the fourth minute, and three minutes later added the second goal when one of the Bilbao defenders failed to clear the ball.
Oyhan Sangeet reduced the difference for the home side in the tenth minute, the first against Real Madrid after five matches in all competitions.
Bilbao, who played the match without four players due to Covid-19, dominated the second half, but Real Madrid held out to collect the three points.
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