They were neighbours in May, side by side at the top of the table. They were twinned in disappointment last week, suffering opening defeats that revealed frailties which may prove ominous.
Leicester and Arsenal are the opposites with the same objective - to record a first win and put false starts behind them.
They meet with Leicester defending the title that Arsenal could, and should, have won but Arsene Wenger able to argue it was others' fault that the underdogs became champions.
Arsenal beat Leicester home and away last season. No other team scored more than two goals in a game against Leicester last season, but Alexis Sanchez got a hat-trick in the Gunners' 5-2 win at the King Power Stadium in September.
The irony, perhaps, is that while Arsenal are often accused of naivety and Leicester picked off unsuspecting victims on the counter-attack last season, Claudio Ranieri's strategy produced no points in their meetings.
In theory, however, his game plan is promising - Arsenal had the most possession last season, Leicester the third least. They prefer to play without the ball.
The three Usain Bolts of the King Power - Jamie Vardy, Ahmed Musa and Demarai Gray - boast the pace to surge clear when they regain it.
And Arsenal conceded four times in a 20-minute blitz by Liverpool last week. As his attempts to sign Germany centre-back Shkodran Mustafi continue, Wenger will restore Laurent Koscielny, who was granted a break after Euro 2016, to add some experience to a callow rearguard.
There is a need to stiffen the spine of his side. Olivier Giroud and Mesut Ozil, other spectators on Sunday, come into consideration. Granit Xhaka, a substitute then, should start.
Sanchez ought to revert to the left wing. With the injured Alex Iwobi and Aaron Ramsey dropping out, Wenger's side could be very different, just as the result needs to be.
The almost obscured fact that a weakened team scored three times against Liverpool illustrates the potency they possess if they can avoid another defensive disaster.
Leicester's issues are different. Both the Community Shield and their 1-2 loss at Hull suggested they are missing the indefatigable N'Golo Kante, now at Chelsea.
His energy often compensated for a numerical disadvantage in the centre of midfield. The long-serving Andy King, a survivor of their League One days, is struggling to deputise.
Leicester excelled at the basics last season. They were clinical in attack and increasingly impressive defensively, particularly at set pieces.
In contrast, last week, they missed clear-cut chances at 0-0 and conceded from a corner.
Lacking the ability of Arsenal, they have less margin for error. When their standards slipped a little, even relegation-favourites Hull beat them.
The loser today could find themselves propping up the early-season table. And, already, sides who set the pace last season would be playing catch-up in this.
LEICESTER V ARSENAL
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