They weren’t just beaten, they were hammered mercilessly by a side well capable of pulling off the most unexpected English top-flight title win since the rebranded Premier League came into being back in 1992.
It leaves City six points adrift of the leaders and marooned in fourth position. Manuel Pellegrini has four months to ensure his tenure is remembered as a successful one.
His and City’s season may be defined by their next five fixtures.
They next face Tottenham Hotspur, who leapfrogged them at the weekend and sit second, before a trip to Chelsea in the FA Cup. Dynamo Kiev in the Champions League last 16 comes after the game at Stamford Bridge, and then two matches against Liverpool—in the League Cup final and the Premier League—bring the run to a close.
We’ll have a good idea of how successful City’s season will be after those games.
Injuries have struck in attacking areas, making that run even more daunting. Jesus Navas suffered a hamstring problem in the win over Sunderland, and David Silva’s ankle trouble flared up again in the defeat to Leicester. Add in long-term absentees Kevin De Bruyne and Samir Nasri, and City are suddenly short of options in the support position behind Sergio Aguero.
All of which increases the importance of Raheem Sterling, City’s 21-year-old forward signed from Liverpool in the summer.
Sterling has had an excellent first season at City. Like any young player, he’s had games where he’s struggled—overwhelmed, it seems, by the demands of playing in a side with such lofty ambitions.
Overall, though, he’s shown more than enough to suggest City have bagged themselves a top-class, long-term attacking option.
He brings pace and width to the side and has an ability to go past players. He’s scored 10 times—more than he managed in any season at Liverpool—showing his quality in front of goal is improving all the time.
The treatment he has received throughout the campaign, from supporters all over the country, has been diabolical, and it probably stems from the media storm that followed his summer move.
He was cast as a mercenary, a player turning his back on the club he loved in favour of money—an analysis that appeared to forget the fact he’s a Londoner who left Queens Park Rangers for Liverpool as a youngster.
The fact he’s been a regular in a Champions League team fighting for honours, surely, has convinced some he made the right move.
The way he’s handled that pressure has been admirable and says much about his maturity and professionalism. Watch any interview with him since joining City—he’s one of the most focused young players in the game, the exact opposite of his media portrayal.
His hat-trick against Bournemouth and his crucial double against Borussia Monchengladbach grabbed the headlines, but it was perhaps his performance away at Sevilla that is his most impressive in a City shirt.
It was a display of quality and maturity. Right from the off, he wanted the ball in what was a difficult atmosphere and looked to take on the Sevilla defenders whenever possible.
That's what City need now—that kind of bravery and willingness to make something happen. In the absence of others, he must shoulder much of the responsibility.
Now is his time to shine. He's been criticised at times this season, but with City in dire need of creativity at a crucial point in the season, he can show people they were wrong to doubt him.
Rob Pollard is Bleacher Report's lead Manchester City correspondent and will be following the club from a Manchester base throughout the 2015/16 season. All quotes were obtained firsthand unless otherwise noted. Follow him on Twitter @RobPollard_.