The Champions League side 22 games unbeaten

And Europe's in-form side is?

Bayern and Manchester City both had claims until their 100% starts to the season ended over the space of 24 hours before the international break. The English club can at least console themselves that, at ten matches, their winning start to 2016/17 lasted longest.

So who does that leave? Real Madrid loom large having gone 21 games without suffering the pain of defeat, since April's 2-0 loss at Wolfsburg (one of only two reverses in 37 outings under Zinédine Zidane). They have subsequently won 15 and drawn six.

However, the UEFA Champions League team on the longest unbeaten run is ... København.

'We can't lose here'
The Danish side have gone 22 matches without defeat (including 20 this season) since a 22 May loss to Hobro – which came just a few days after the capital club had won the title, and when their minds were arguably not on the job.

At home, FCK have been particularly fearsome; they have long since broken Midtjylland's Superliga record of 29 home games unbeaten, their streak now stretching back 37 matches to 15 August 2014. As striker Andreas Cornelius puts it: "We have a belief we can't lose here."

As their matchday three trip to Leicester looms, their spirit of collective endeavour is not unlike that of the team that won the Premier League under Claudio Ranieri last term. Still euphoric after matchday two's 4-0 thrashing of Club Brugge, midfielder Thomas Delaney said: "We are proving that even though other clubs in the UEFA Champions League group stage have bigger budgets than us and maybe more quality in certain positions, we have a stronger group."

Erik Johansson (L), FCK's secret weapon?©AFP/Getty Images

Defensive partnership
Coach Ståle Solbakken called that Club Brugge scalp "a demonstration of power for the history books" but it is defensive solidity that has underpinned their recent run. Centre-backs Mathias 'Zanka' Jørgensen and Erik Johansson have not lost in their 30 games as a partnership (W20 D10), keeping clean sheets in more than half of them.

Signed from Gent in January, Swede Johansson may have been the missing piece of the jigsaw; he and Jørgensen have each gone on record to say their current partner is the best defender they have worked with.

Both Real Madrid and FCK have some way to go, however, to beat the record of 62 matches without a loss set by Celtic a century ago, albeit one established while playing only in the league.

Longest unbeaten runs in all competitions
62 Celtic 1915–17
45 Dinamo Zagreb 2014–15
43 Juventus 2011–12
42 Milan 1991–92
40 Nottingham Forest 1978
39 Barcelona 2015–16
36 Milan 1991–92
34 Real Madrid 1988–89
33 Manchester United 1998–99

UEFA Champions League sides unbeaten in 2016/17
20 – København (DEN) W12 D8
10 – Real Madrid (ESP) W6 D4
9 – Atlético Madrid (ESP) W6 D3
9 – Beşiktaş (TUR) W4 D5

Beşiktaş are unbeaten this season©AFP/Getty Images