Barca had taken the lead through Marcos Alonso in the seventh minute but he then became the villain as he caught Joselu's heel inside the box midway through the second half. The Espanyol striker rolled the ball down the middle from the spot to earn his side a point.
The game threatened to spiral out of control from there, with both sides reduced to 10 men in the final 15 minutes, as Barca desperately sought a winner which never arrived. Here is ESPN's Sam Marsden with reaction and analysis from Camp Nou.
1. Barcelona's winning run halted by Espanyol
Barcelona's five-game winning run came to an end in LaLiga as they were held to a 1-1 draw by Espanyol in a fiery Catalan derby at Camp Nou on Saturday, leaving Xavi Hernandez's side level with Real Madrid at the top of the table.
Marcos Alonso's early header gave Barca the lead, but what had been a relatively straightforward match turned on its head when Joselu equalised from the penalty spot in the 73rd minute. It was the first goal Barca have conceded at home in the league this season.
The game then spiralled out of control, with referee Antonio Mateu Lahoz taking centre stage. Jordi Alba and Vinicius Souza were sent off to leave both sides a man short and Barca chasing a winner to restore their two-point lead over Madrid, who beat Real Valladolid on Friday. However, Espanyol goalkeeper Alvaro Fernandez produced two brilliant saves on shots by Robert Lewandowski -- who was only playing after a three-game suspension was placed on hold on Friday -- and Andreas Christensen to earn a precious point for the away side.
Barca will reflect on what happened before the chaos, though, and the lack of quality in the final third throughout a first hour they largely dominated. Questions will be also asked about Raphinha, who was off-colour, and Ansu Fati, who has still not looked like the teenager who burst onto the scene since a string of injuries derailed his progress.
2. Mateu Lahoz again in the spotlight
Referee Mateu cannot help but become the centre of attention in almost every match he's assigned to. He did so in the World Cup quarterfinal between Argentina and Netherlands, issuing a FIFA record 17 yellow cards, and he managed to do so here in his first LaLiga game since the break.
After bizarrely hugging Barca coach Xavi in the first half, he lost control of the game in a wild 10 minutes in the second half, sparked by his decision to award Espanyol a penalty. What followed was six yellow cards in four minutes including two for Alba, who received his marching orders. Two minutes later, Vinicius picked up his second booking to even up the match at 10 vs. 10.
What followed was a brawl between both teams, with Mateu dropping his yellow card in the excitement and then showing a red to Leandro Cabrera for what appeared to be a stamp on Lewandowski. Following a lengthy VAR review, Cabrera's dismissal was overturned, which left the Camp Nou crowd seething. They had been on Mateu's case from the start, jeering his name before the match, but the noise was turned up now. And the jeers were replaced by expletive-ridden chants.
3. Espanyol show they're better than they seem in LaLiga
Espanyol are just a point above the relegation zone, but even before this match at Camp Nou, the feeling was that they are better than their league standing suggests. That would appear true after they produced a performance that showed they should be too good to be dragged into a relegation battle.
In Joselu, they have one of the league's most prolific strikers, who now has eight goals for the season. Behind him, Sergi Darder is one the most underrated midfielders in Spain and Diego Martinez, as he proved during his time at Granada, is a very astute coach. They now must replicate the fire they played with against Barca in every game. Luckily, then, they have another derby coming up against Girona next week.
Barcelona (4-3-3): Marc-Andre ter Stegen 6; Sergi Roberto 6, Andreas Christensen 7, Marcos Alonso 6, Jordi Alba 5; Gavi 7, Frenkie de Jong 7, Pedri 7; Raphinha 5, Robert Lewandowski 6, Ansu Fati 5.
Subs: Sergio Busquets 6, Ferran Torres 6, Ousmane Dembele 6, Alex Balde 6, Jules Kounde 6.
Espanyol (4-2-3-1): Alvaro Fernandez 8; Oscar Gil 6, Sergi Gomez 6, Leandro Cabrera 6, Brian Olivan 6; Vinicius 5, Fernando Calero 5; Nicolas Melamed 6, Sergi Darder 5, Martin Braithwaite 6; Joselu 7.
Subs: Javier Puado 6, Edu Exposito 6, Simo 6, Aleix Vidal 6, Ruben Sanchez 6.
Best and worst performers
BEST: Alvaro Fernandez, Espanyol
The Espanyol stopper made six saves, but he saved his best until last, keeping out Christensen and Lewandowski in the final stages of the game.
WORST: Raphinha, Barcelona
Saw a lot of the ball in the first half but was let down by his delivery. His afternoon was summed up when he received a short corner from Frenkie de Jong and let the ball escape for a goal kick with his first touch.
Highlights and notable moments
Like so many teams this weekend, Barcelona held a silent tribute before the match to Pele, who passed away on Thursday.
RIP Pelé pic.twitter.com/JT0IK7hkWR— FC Barcelona (@FCBarcelona) December 31, 2022
Hey, remember this guy from the World Cup? Never a dull moment when he's got the whistle, that's for sure.
Mateu Lahoz gave out 14 bookings, three red cards and overturned one of those sendings off during Barcelona vs. Espanyol.— ESPN FC (@ESPNFC) December 31, 2022
He was the referee who gave out 17 yellow cards during Argentina vs. Netherlands at the World Cup.
At least he's consistent 😅 pic.twitter.com/t3oS5AbW05
And in a chaotic spell towards the end of the second half, Espanyol got a crucial equalizer and held on for a point that'll give them confidence heading into 2023.
Marcos Alonso gives away a penalty to Espanyol, which striker Joselu cooly converts for 1-1.
After the match: What the players and managers said
Espanyol manager Diego Martinez: "I am very proud of these players. They competed well with the DNA of this club, the strength of feeling that we have. We suffered when we had to, knowing who we were playing against. We were able to control our emotions when we had to. The point strengthens what we are doing, but more than anything I am really proud of the players. They stuck to the plan. It was not easy. When you go behind, sometimes you lose your heads, but they kept theirs. They competed really well and deserved the point."
Barcelona manager Xavi: "It's our fault we drew. We can speak about the referee of other things, but it's down to us. When you have so many chances, get forward so many times, but aren't clinical, it is your fault. An excellent first half an hour but we didn't know how to kill the game off. In the second half, we weren't at the rhythm or intensity required. We end the league top with Real Madrid, but it's two points dropped today and it's our fault."
Xavi on referee Lahoz: "The game got away from him today. He was giving out cards without any reason and lost control of the match. But it's not his fault today, it's our fault we dropped points."
Key stats (via ESPN Stats & Information)
Marcos Alonso's goal was his first in LaLiga (9 career games played)
Coming into this game, Barcelona had won 15 straight meetings against Espanyol at Camp Nou in all competitions since a 2-1 LaLiga loss in 2009
Barcelona: Xavi's side have a Copa del Rey trip to third-tier CF Intercity on Wednesday (Jan. 4), and you can expect a rotated XI to feature because their next LaLiga game is at Atletico Madrid (Jan. 8). With the fixtures coming thick and fast after the World Cup break and Christmas, they can't afford to slip up.
Espanyol: There's no rest for the struggling LaLiga side in the new year. They get a trickier Copa del Rey game on Tuesday (Jan. 3) against Celta Vigo before a home date with Girona in LaLiga on Jan. 7.