Manchester City's trip to Leicester last season was one of the low points of their season. The 4-2 defeat, which was made only marginally respectable by two consolation goals for Pep Guardiola's side in the final eight minutes, was perhaps the second-worst result of the campaign behind the 4-0 loss at Everton.
That afternoon at Leicester, some fans began to question the logic in Guardiola's methods. Pablo Zabaleta was asked to tuck into midfield when City had the ball, while a remaining back three of Aleksandar Kolarov, Bacary Sagna and John Stones was all over the show. All of that was going on in front of a hapless Claudio Bravo.
There were mistakes everywhere. The defensive line was regularly crooked, as some tried to catch the Leicester strikers offside while others dropped to cover; closing down was at best lazy, and at worst non-existent; and the icing on the bad-performance cake was Stones providing a blind pass to assist Jamie Vardy's hat trick goal in the second half.
Just under a year on from that fixture, City go to the King Power looking a completely different team at the back. Ederson's arrival has added confidence to the passing ethos, while Stones and Nicolas Otamendi have formed an excellent partnership in front of him. The pair seem to know when each has to cover the other and both have been far more comfortable on the ball.
The addition of Kyle Walker has provided much-needed pace and consistency on the right flank, and Fabian Delph has been a shock revelation on the opposite side. His central midfield background has meant he's been more than comfortable stepping into the middle when City have the ball, rather than overlapping like a traditional full-back would.
If you'd told a City fan even as recently as last August their team would be comfortable defending without Vincent Kompany in the back four, you'd have been laughed out of the room. However, the reality is when the captain is fit again, it's difficult to see how he gets back into the side, barring others being unavailable.
Yet as Guardiola prepares for a trip to Leicester, he must be wary of a breakdown in his defence because of one small detail. Otamendi is banned, having picked up his fifth yellow card of the season in the 3-1 win over Arsenal. It means City's best partnership for some time will have to be broken up.
It's not ideal, especially as a resurgent Leicester will sense an opportunity to become only the second team to take points off Guardiola this season, perhaps even feeling they may be the first to beat the league leaders if they can exploit whoever comes in to replace Otamendi.
With Kompany sidelined with an injury picked up on international duty at the beginning of September, Guardiola's options are looking limited. His only natural options for centre-back alongside Stones are Eliaquim Mangala and Tosin Adarabioyo. However, the former he wanted rid of to make way for Jonny Evans last summer, while the latter is an inexperienced rookie with just three starts to his name, one of which was as part of Manuel Pellegrini's team of sacrificial lambs in the 5-1 FA Cup fifth round defeat to Chelsea in 2016.
With roughly 301 senior minutes under his belt, the youngster could be a risk, though it has to be said that sometimes there's nothing quite like being thrown in at the deep end to see if a player will sink or swim.
An out-of-position Danilo could also be the answer. He arrived in the summer with the promise of being a utility man, able to play in defence on both the left and right flanks and in central midfield, but has rarely been seen thanks to the form of Walker, Benjamin Mendy, and Delph.
For a more in-form option, Fernandinho could drop into the back four -- though, as impressive as he's been since returning from a long injury, Ilkay Gundogan hasn't given the team the same sort of impetus the Brazilian has when used as the midfield anchor.
Whatever the manager decides, City will have something of a makeshift backline despite investing over £150m last summer in the defence.
Despite the hearty goal-scoring form the club have been in this season, the rearguard has truly allowed them to open up an eight-point lead at the top of the Premier League. That solid foundation has been the bedrock for the destructive attacking displays that have left both fans and neutrals purring.
Otamendi's suspension for the trip to Leicester might seem like a small problem, but it's in this sort of situation where we'll really see how well equipped City are to cope with the issues they failed to deal with last season.