"Get your mentality right, get your attitude right. If some of you don't want to be here, leave. I'm detecting a bit of a malaise among them where sometimes they're not as good as they think they are."
Ferencvaros didn't just crush Celtic's Champions League hopes last season, they also sparked the beginning of the end for the Glasgow club's unrivalled era of success.
Neil Lennon let loose on his players in a post-match outburst, publicly laying bare dressing-room divisions, and he departed as manager in the subsequent months as Celtic's season imploded.
Yet while Celtic finished the campaign trophyless for the first time in a decade, Ferencvaros prospered on the domestic and European stage.
With the sides meeting again, 14 months on, in the Europa League on Tuesday, what makes the Hungarians a threat?
Last season's Celtic scalp 'huge'
The upset against Celtic was a launchpad for Ferencvaros as they reached the Champions League group stage for the first time in 25 years.
Dinamo Zagreb and Molde were subsequently dispatched to make the dream reality, but it was the triumph in the second qualifying round - Celtic's earliest Champions League exit since 2005 - that really resonated in Hungary.
Celtic started without a striker but still created plenty of chances, levelling through Ryan Christie after David Siger's early opener in the one-legged tie. Tokmac Nguen pounced on defensive hesitancy to score a late breakaway winner that carried significant repercussions.
"It was huge - one of the biggest wins they've had in a long time," says Hungarian football writer Tomasz Mortimer.
"Beating Dinamo Zagreb is big in a regional sense. But Celtic is different with the history of the club and because British football has such a huge lure and love among Hungarian fans.
"Ferencvaros have just been getting better and better in recent years. They've got a lot of money from government backing and they have a really strong fanbase - about 50% of the country support Ferencvaros."
New boss Stoger makes his mark
A sleeping giant had awoken, but the manager who roused them from their slumber departed this summer.
After three successive domestic titles, and returning the club to the group stages of the Europa League and Champions League, Ukraine legend Sergei Rebrov moved on.
It means both sides approach Tuesday's tie under a new boss, but in contrast to Celtic's upheaval and major rebuild under Ange Postecoglou, the transition at Ferencvaros has been mainly smooth.
Former Borussia Dortmund and Cologne manager Peter Stoger has taken the reins and built from a position of strength while implementing a more expansive style of play.
Ferencvaros retained their best players this summer and supplemented the squad with the likes of former Premier League midfielders Muhammed Besic and Marko Marin, Bosnia-Herzegovina midfielder Stjepan Loncar, and 20-year-old Serbia winger Zeljko Gavric.
The pick of the new arrivals, though, is Morocco forward Ryan Mmaee, who joins his defender brother Samy in the squad and has nine goals in 16 appearances.
"It's the best team Hungary at club level have produced since the 1980s when Videoton made the Uefa Cup final," says Mortimer. "I thought that last year and the team has even got better from there.
"Almost every player is an international and Mmaee and Nugen - who scored the winner at Celtic Park - are the two standouts. Mmaee has been awesome, they unearthed a gem there.
"Nguen is a level above Hungarian football. It's a surprise he's still at the club, just because of how good he is."
Who will grab first points?
Ferencvaros came through three Champions League qualifying rounds this season - including victory over Slavia Prague - before losing the play-off to Young Boys and dropping into the Europa League.
They led away to Bayer Leverkusen before succumbing 2-1, and two late goals at home to Real Betis then condemned Stoger's men to a 3-1 defeat.
It leaves both Ferencvaros and Celtic seeking their first points when they go head-to-head in Glasgow.
The Hungarian champions' preparations were hampered by a shock 2-1 home defeat by Zalaegerszegi TE on Saturday, ending their run of six straight league wins.
Their lead at the top of the Hungarian league is now down to goal difference, but they travel to Glasgow with belief, albeit to face much-changed opponents.
Of Celtic's starting line-up in August 2020, only one player - current captain Callum McGregor - is likely to face the Hungarians again. Six have left the club, three - Christopher Jullien, Greg Taylor and James Forrest - are injured, while goalkeeper Vasilis Barkas is so far down the pecking order he's as good as gone.
"Because of last year, and the more expansive style of football they are playing under Stoger, it gives Ferencvaros a lot of confidence," added Mortimer.
"The team will be more open than they were last time when they played almost 'bunker football' under Rebrov."