Real Madrid built up a commanding lead in the first half of El Clasico at the Estadio Di Stefano.
After Karim Benzema's opener, the hosts were awarded a freekick on the edge of the box when Ronald Araujo brought down Vinicius.
Kroos stepped up to take, with his shot hitting Sergino Dest on the back and finding a way past Jordi Alba on the line.
The German midfielder became the first Real Madrid player to score a freekick in a Clasico since Roberto Carlos did so in 2000.
Source: m.allfootballapp.com