It's hard enough to compete with Barcelona with 11 men. With 10 players, it's pretty much impossible.
Doesn't Manchester City know it.
City has played Barcelona five times in the last four seasons in the Champions League and ended a game with a full complement of players only once. It's one of the main reasons City has lost all five of those games.
Ahead of the latest meeting, in Manchester on Tuesday, City manager Pep Guardiola has impressed on his players the importance of keeping discipline and a cool head.
"You have to learn," Guardiola said Monday. "[Former City manager] Manuel [Pellegrini] lived through that, sometimes they were unfair, the last time it was from a mistake. But at that level, it's impossible to achieve your targets [with 10 men].
"It's football, and football is a game of mistakes."
The roll call of red cards are as follows: Martin Demichelis (professional foul) and Pablo Zabaleta (two bookings) in the last 16 in the 2013-14 campaign; Gael Clichy (two bookings) in the last 16 in the 2014-15 campaign; and Claudio Bravo (deliberate handball outside the box) in a 4-0 loss in the group stage two weeks ago.
The dismissals can be put down to a number of factors – the pressure of the occasion, the difficulty of handling elusive players such as Lionel Messi, Luis Suarez and Neymar, and simple brain freezes as with Bravo when he compounded his error of misplacing a pass outside the area by blocking a return shot by Suarez.
"Individual errors are part of football," Barcelona coach Luis Enrique said. "It's difficult to evaluate whether or not these are one-off errors or it's because the other team [Barcelona] pressured them.
"But I think the [4-0] result didn't really reflect the way the match went."
City has had its disciplinary issues this season. Aside from Bravo's red card, Sergio Aguero was handed a retrospective three-match ban for elbowing West Ham defender Winston Reid in a Premier League game, and Nolito also got a three-match suspension for aiming a head-butt at Bournemouth defender Adam Smith in the league.
Before Bravo's sending-off in the 53rd minute at Camp Nou, City played well, created chances and was perhaps unfortunate to be behind 1-0. With 10 men, City unravelled and Messi completed another Champions League hat trick. It follows 2-1 and 2-0 losses for City in 2014, and 2-1 and 1-0 losses in 2015.
Guardiola said City will have to play "almost perfectly" to beat Barcelona and keep qualification in the team's own hands.
"I think we know what we have to do to beat them, and they know us," Guardiola said. "We will try it again … I have never entered a match thinking we can't win."
Luis Enrique expects Guardiola, his former teammate for Barcelona and Spain, to make some tweaks in personnel or tactics.
"I sense there will be changes," he said. "We know Pep and we know his ideas. We have to be very attentive to what they do. He will try to touch the correct key to get the right result. I love his philosophy, I love his ideas."