Like he's done so many times before on the big stage, Sergio Ramos came through in the clutch with a late goal to rescue Real Madrid.
Ramos's 90th-minute header off Luka Modric's free kick forced a 1-1 draw in El Clasico, with Barcelona dropping points it thought it had in the bag after Luis Suarez's opening goal at Camp Nou on Saturday.
Real Madrid maintains its six-point lead over Barcelona through 14 games, and it marks a third consecutive 1-1 draw for Barcelona in league play, where it rarely drops points on a consistent basis.
Playing without the injured Gareth Bale, Real Madrid was denied an early penalty shout when Lucas Vazquez went down after a challenge by Javier Mascherano, though no foul or PK was called.
On the other end, a fantastic sequence from Barcelona nearly led to a goal for Sergi Roberto, though the attack's perfection broke down at the end following a slip by Neymar.
Following a pair of Cristiano Ronaldo shots saved by Marc Andre ter Stegen, Barcelona had a penalty shout of its own go unheard, after Dani Carvajal was absolved from a handball in the box. The teams went into the halftime break scoreless.
Suarez finally opened the scoring in the 53rd minute. Neymar's service off a free kick from the left found Suarez some eight yards out, and he positioned himself to head it by Keylor Navas to release some of the tension at Camp Nou.
Neymar nearly made it 2-0 after a spectacular individual effort 1-v-1 with Carvajal, but the Brazilian star put his right-footed blast just over the bar, much to his own disappointment.
Messi had a chance to make it 2-0 himself, after Andres Iniesta, who came on in the 60th minute to return from injury, found him with a sensational, defense-splitting pass. The Argentine star put his chance wide of the far post, though, keeping Real Madrid within a goal.
That came back to bite Barcelona, as Ronaldo had a golden chance in the 89th minute to pull level. Marcelo's cross to the far post found Ronaldo for a leaping header, but Jordi Alba came to the rescue with a goal line block. There was no stopping Ramos's 90th-minute header, though, as he beat ter Stegen with a powerful attempt off Modric's sublime free kick to make it 1-1.
Prior to the game, the Camp Nou faithful was at its finest, displaying a beautiful mosaic that spanned the whole stadium.
The two rival sides also came together to pay tribute to Chapecoense, the Brazilian club decimated by the fatal plane crash in Colombia earlier in the week.
Barcelona has sole possession of second place after the result, with Sevilla falling at Granada 2-1 Saturday to fall further off the pace.
Real Madrid hosts Deportivo de la Coruña in its next league game, while Barcelona travels to Osasuna.