Leverkusen were cast in the role of nearly men by finishing second on five occasions in the league, while losing three German Cup finals.
The German equivalent of "Neverkusen" is "Vizekusen", which translates to "the champions of second place".
With just two major trophies in their history, and none since 1993, some began to wonder if the club was cursed to endure eternal bridesmaid status.
Alonso however had other ideas, taking the club to a league title in his first full season in charge, with an historic treble still very much on the horizon for the unbeaten side.
'No-one will say it anymore'
On the final day of the 1999-2000 season, Leverkusen needed just a point against Bavarian minnows Unterhaching, now in the third division, for their first Bundesliga title.
However, they lost 2-0 in a match remembered for Michael Ballack's calamitous own goal, allowing Bayern Munich to swoop in for another title after beating Werder Bremen.
Leverkusen's nadir came in 2002 when the club somehow emerged empty-handed despite being five points clear in the league with three games remaining, while also qualifying for the German Cup and Champions League finals.
German national team sporting director Rudi Voeller, who held the same position at Leverkusen for the best part of two decades having also played for and coached the club, credits Alonso for silencing the jibes.
"At the very least, nobody will say 'Vizekusen' anymore," Voeller told AFP subsidiary SID and other media on Thursday, revealing "it's something that really angered me over the years."
Voeller backed the club to continue on, particularly after Alonso turned down apparent interest from Liverpool and Bayern to stay in Leverkusen.
"Besides winning some titles, it could kick-start an era. Xabi Alonso will stay as coach, we'll hang onto most players and we'll be in the Champions League."
Sitting at 34,000 members at the start of the season, Leverkusen cracked the 54,000 mark for the first time in April.
German fans have joked that Alonso's winning pedigree is so strong it broke the Leverkusen curse. More than a few have said the famously trophyless Harry Kane had the opposite impact at Bayern, breaking their 11-year title run.
It is true that few players have won as much as Alonso. Whether at club or international level, success followed the Basque everywhere he went.
Alonso won league titles in Germany and Spain, the Champions League with Liverpool and Real Madrid along with several domestic cups.
With Spain, Alonso won two European titles either side of lifting the World Cup in 2010.
"I heard a fair bit about 'Neverkusen' and 'Vizekusen' when I got here," said Alonso on Friday, adding it would be a "huge honour" to finally break the curse.
'He does something to you'
Besides creating a clear playing style and motivating almost every member of his squad to hit career-best form, Alonso has expertly played down expectations even as the reality of a league title came clearly into view.
In an interview with AFP in November, he said title talk should wait until April.
When April came around, he asked fans to wait a little longer.
"The fans are intelligent and they can remember what happened in the past. They've got patience."
"We want to celebrate when we can celebrate. And now it is not the moment to celebrate, it's the moment to work and to prepare."
Midfield enforcer Robert Andrich, Leverkusen's unsung hero in the centre of the park, credited Alonso with changing the way the club and the players think of themselves.
"He's sometimes a bit shy in his outward appearance, but you notice that he does something to you," said Andrich.
"I think he brought this Real Madrid winner mentality into us."
Andrich, 29, was selected to represent Germany for the first time this season -- a story reflected throughout the Leverkusen squad.
Seven players have received their first national team calls -- Andrich, Alex Grimaldo, Victor Boniface, Nathan Tella, Matej Kovar, Jeremie Frimpong and Amine Adli.
An eighth, Arthur, was named in the Brazil squad for the first time in Alonso's debut season at the club.
Frimpong summed up Alonso's impact on the club and the fans, telling reporters "he changed Leverkusen".
