What's more, Barcelona delegate Carles Naval was by his side, also out for blood, after the hosts' wild celebrations after their 3-1 Champions League win went too far.
It took Messi's friend Sergio Aguero to calm things down, as explained by Spanish radio station Cadena Ser after a thrilling night at the Etihad Stadium.
Showing emotion and getting angry is fine, but what Barcelona cannot do is panic, even though by the end of the second half, they had been battered black and blue.
This was not as brutal a result as the 4-0 beatdown they inflicted on Manchester City at Camp Nou a couple of weeks ago, but the score was firmly settled.
The game was similar to the first, except with roles reversed. This time it was Barcelona who played reasonably well in the first half before being crushed in the second.
City hadn't deserved the heavy defeat they suffered, influenced heavily by Claudio Bravo's dismissal and some poor individual errors which broke up a strong team display.
And this time it was Barcelona making crucial errors that gave the hosts momentum.
Luis Enrique attributed the shift in the game to Sergi Roberto's first-half mistake that saw him give the ball to City on the edge of his own box with a wayward pass. He said, per Sport:
We played 40 spectacular minutes, especially on this stage against a top rival. But we committed a key mistake and that hurt us because we are not machines. It's a shame that we have made that error for the first goal and from there on we had a tough time. When you concede like that, it's normal that you have a bad spell. During that moment we wanted to continue to dominate the game, but it wasn't possible because of errors we made and pressure from City, too. We didn't have much of the ball and City took advantage of our errors.
The coach was right about Barcelona's first half. With the exception of the Celtic game—although perhaps not if the quality of opposition is taken into account—this was the best football they have played all season.
Barcelona started the game deep, with City intent on dominating the ball and attacking. "Fine," said Luis Enrique's team. "You do that."
And in the 21st minute, they gave a perfect demonstration of what this Barcelona team can do that Pep Guardiola's side often couldn't.
Javier Mascherano won the ball back in his area and found Messi, who sprang Neymar. The Brazilian carried the ball forward, surging into City's half and towards their box, when he completed his "70-yard one-two" with Messi, who finished coolly.
It was a counter-attack like a hot knife through butter, and Barcelona slid it out and attempted to slice City up completely. On another day, they could have.
"In the first half we could have killed the game off with another goal," admitted Luis Suarez, per Sport. "We have to take the good and the bad from the game. At 2-1 we had a really good chance to make it 2-2, but it's difficult once it goes to 3-1."
Suarez was one of the culpable parties, still badly off his game. The forward's touch was poor, he rarely got in dangerous positions, and when he did, he executed his finish badly.
His one useful contribution was to surge forward and set up Andre Gomes, but the midfielder cracked a strike against the crossbar.
There were further errors made by the Catalans. Lucas Digne gave the ball away on the left flank that led to a City counter, then Sergio Busquets clumsily fouled David Silva on the edge of his own box.
Kevin De Bruyne's free-kick was good, but Marc-Andre ter Stegen got a hand to it and probably should have kept it out. Three mistakes that led to a goal.
Barcelona's left flank was City's chosen point of access through Barcelona's defence, for three reasons.
One, the dynamism of Raheem Sterling and the speed of Jesus Navas were potent weapons.
Two, Digne is the backup for Jordi Alba and is still bedding in at the club.
And three, unlike on the other side of the pitch, where Ivan Rakitic helps Sergi Roberto—and formerly Dani Alves—with his defensive duties, Barcelona's left interior isn't as useful in that regard.
Usually it's Andres Iniesta who tries to help but isn't the strongest at tackling, but on this occasion it was Andre Gomes.
The Portuguese midfielder had one of his best games for the club, including a fantastic piece of defending to deny Silva a chance to shoot on goal, but he played an advanced role and wasn't often found supporting Digne. And, of course, Neymar cannot be relied upon in that regard, although he did get a booking for clipping Sterling's heels.
Barcelona's mistakes wore them down, and City began to dominate. One reason for Barcelona not to panic is the differing levels of motivation each side had going into the game.
Guardiola had claimed this was a "final" for his team going into the match, with his side needing a win to keep their hopes of qualifying for the next round of the Champions League alive.
Barcelona, top of the group with nine points from three games before this one, were cruising.
"The stimuli appear when they need to appear," said Lucho after his team's narrow win over Granada at the weekend.
It seemed in the first half like the occasion was motivation enough for Barcelona, but it just turned out the hosts wanted—and needed—the victory more.
That is not the case on Sunday when they head to Sevilla. That is a huge clash in La Liga and also why Barcelona cannot panic at this result but calmly analyse what went wrong and try to change it.
And to remember the quality of their first-half performance.
"[In the] first 38 minutes we saw the best team in the world. If they score another it's done," said Pep Guardiola, per Sport.
That is what Barcelona need to remember. That even in their current state, without captain Iniesta, without the best centre-back in the world in Gerard Pique, without first-choice left-back Jordi Alba, they are still capable of producing football like this.
Panicking, changing their style, thinking too much about their game will only serve to weaken them ahead of the challenges ahead.
Suarez, despite his own shoddy display, had the right attitude. "This won't affect us at all," he insisted.
"We're here for this, to perform in every game and even more so at a club like Barca. We've lost, but now we have to forget it and think about Sevilla, which is an important game."
Rik Sharma is Bleacher Report's lead Barcelona correspondent. All information and quotes obtained firsthand unless specified. Follow him on Twitter here: @riksharma.