(CNN) -- Cristiano Ronaldo scored the only goal of the match with a stunning backheel as Real Madrid beat Rayo Vallecano to stay 10 points clear in the Spanish title race Sunday. 

Real had to work hard to emerge on top in the capital derby at the Vallecas while arch-rivals Barcelona won 2-1 against Atletico Madrid in the late kickoff to avoid falling further behind Jose Mourinho's men. 

The reigning champions owed their win to a Lionel Messi free-kick in the 80th minute. It was his 28th league goal of the season, one fewer than Ronaldo. 

Dani Alves opened the scoring on 36 minutes but Radamel Falcao equalized at the beginning of the second half for the home side. 

Earlier, the first half of the clash between the Madrid rivals was short of chances, but Rayo came closest to scoring as Michu rattled the woodwork with Iker Casillas beaten. 

Ronaldo struck shortly after the break following a corner. He was running away to chase a loose ball, but then fashioned an incredible backheeled effort which flew into the net. 

"A backheel is always different. It was a great goal but I'm not sure if it was the best of my career -- I have to see it again on TV," Ronaldo told AFP. 

Jose Callejon later wasted a chance to double the lead for Los Blancos to calm their nerves. 

Ronaldo was also denied a second by home keeper Joel late on before the home side lost Michu to a red card for a rash challenge. 
on what day of the week?
points clear in the Spanish title race Sunday. 