Real Madrid still has two games in hand on Atletico, but the two face each other in the Madrid derby on Saturday.
Diego Simeone's men were irresistible at times in the first half at the Vicente Calderon and, although they faded a little after the break, their brilliant defence helped secure a fifth successive LaLiga win, piling more pressure on Sevilla ahead of their trip to Barcelona on Wednesday.
"Since 2017 began, we have been playing much better, a much more balanced team, more consistent in our play", Simeone said.
Left-back Theo, 19, has impressed on loan at Alaves and Marca reported earlier this week that Real would pay his €24 million release clause, breaking an unwritten gentlemen's agreement preventing such transfers between the clubs. "I don't remember having scored two goals in consecutive games in the league".
The deal is possible but you have a pissed-off Atletico, who will try to create hurdles for Real Madrid and you also have a fairly resolute Real Madrid, who are keen to line up Marcelo's replacement even if Theo is just one name on Real Madrid's list.More news: The Defenders announces premiere date in first teaser
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Atletico has won eight of its last 10 league matches and is enjoying its best run of the season.
Nonetheless, Diego Simeone's charges managed to hold out until the final whistle to claim their fifth straight league win.
Leader Real Madrid plays at Leganes on Wednesday to defend its two-point lead over Barcelona.
A third defeat in four games sees Sociedad slip to seventh as Villarreal and Athletic Bilbao boosted their chances of Europa League qualification.
Villarreal move back into fifth thanks to Adrian Lopez's 47th minute goal which gave them a 1-0 win away to struggling Betis, who rarely looked like getting anything from the game.