Madrid overturned a two-goal deficit to trump Villarreal 3-2 in a stunning comeback away from home on Sunday.
Goals from Gareth Bale, Cristiano Ronaldo and Alvaro Morata ensured Madrid returned to the top of the table, ahead of bitter rivals Barcelona, who prevailed 2-1 at Atletico Madrid earlier in the day.
Marcelo - the provider for substitute Morata's 83rd-minute winner - knows what has to be done for Madrid to claim the La Liga crown for the first time since 2012.
"Barcelona did what they needed to do by going to a very difficult place and winning," the Brazil full-back said.
"But it's in our hands and if we win all of games, we'll be champions."
Madrid captain Sergio Ramos is braced for an intense end to the season as the capital club also bid to retain their Champions League crown.
"It's going to be very difficult, last year we were playing for the league right up until the very end and this year it looks like it's going to be the same," Ramos said.
"Any team we come up against will try to make it very difficult for us. We want to keep picking up three points in order to win the title. Fortunately it’s in our hands and we're focused on continuing to improve."
Back-to-back defeats appeared on the cards for Madrid when Manu Trigueros and Cedric Bakambu put Villarreal 2-0 ahead by the 56th minute.
But Bale reduced the deficit in the 64th minute and Ronaldo equalised from the penalty spot with 16 minutes remaining before Morata headed home the winner.
"We didn't give up on the game and everyone worked and battled hard as a team and ultimately we managed to get the win. It's important to highlight the commitment from all of my team-mates," Marcelo added.
"Their goals came off second balls and that's something we need to work on and we'll take a look at the video coverage to improve on that. We've picked up the three points, but we need to use this game to ensure that we don't concede more goals, because we're not always going to be able to produce comebacks."