Picture : Yesterday, Josep Stanisic scored in minute ...97 to keep Bayer Leverkusen unbeaten against Roma !

Bayer Leverkusen, the best in Europe in ICC era – but not yet overall

Bayer Leverkusen continue their fantastic series.
Xabi Alonso's side have been unbeaten in all competitions since the very start of this season, with a total of 49 games, including the second leg of the Europa League semi-final against Roma (2-2).
This is their new record. Bayer have now surpassed Benfica's 48-game streak of 1963-1965, which was previously the longest in this category in Europe since the introduction of international club competitions under the auspices of UEFA.
Here we publish for the first time the all-time global historical ranking of the clubs’ unbeaten streaks in all competitions.
As you can see, Bayer take 4th place in it. Above them, only one African team (Al Ahly, 55 matches) and two European sides from those distant times when there were no major international competitions at club level (Celtic, 66 games in 1915-1917) or they did not participate in them (Union Saint-Gilloise, 60 games in 1933-1935).
It was obviously easier to accumulate super-long streaks while cooking exclusively in the cauldron of national tournaments. 
Nevertheless, this ranking shows that Bayer still have room for further feats.

1CelticScotland66531362   4    20/11/191514/04/1917
2Union SGBelgium60441660        08/01/193303/02/1935
3Al-AhlyEgypt55478382 1 14   12/07/200427/11/2005 
4Bayer LeverkusenGermany49409325    12  12/08/2023 
5BenficaPortugal4838103311   4   22/12/196307/02/1965
6Boca JuniorsArgentina4842638   10    06/04/192424/10/1926
 Lincoln Red ImpsGibraltar48408407 1     20/05/201017/04/2012
7Dinamo ZagrebCroatia452916316   71  30/11/201425/09/2015
8RijekaSlovenia453312385    2  09/04/201629/04/2017
 Lincoln Red ImpsGibraltar4538730852     17/03/200720/04/2009
9RangersScotland443682934  8   19/08/199217/03/1993
10AjaxNetherlands4337630  1 11  101/03/199524/12/1995
11JuventusItaly432617394       22/05/201113/05/2012
12MilanItaly42339286 1 7   18/04/199207/03/1993
13CelticNetherlands423752952  6   27/11/201619/08/2017
14Real MadridSpain40319234   10 1209/04/201612/01/2017
15NottinghamEngland40211929 61 4   14/03/197825/11/1978
16Boca JuniorsArgentina40291140        05/05/199802/06/1999

Comments to the table:
NL = National League (top divisions) 
NC = National Cup
LC = League Cup
NS = National Super Cup
OC = other relevant national Cups 
CL = Champions’ League and its analogue in all confederations (including European Cup era)
EL = Europa League
SC = UEFA Super Cup
WC = Club World Cup
Tie-breaker: more wins in international competitions.
Not classified are teams from the leagues below top 100