Patrick Kisnorbo said a sleeping giant has awoken after Leeds United secured Premier League promotion following a 16-year absence amid wild celebrations in West Yorkshire.
Not since 2004 have Leeds featured in the Premier League but second-placed West Brom's 2-1 defeat at Championship strugglers Huddersfield Town on Friday ensured the club's long-awaited return to England's top flight with two matches remaining.
Leeds reached the Champions League semi-finals in 2001 but the Yorkshire outfit imploded financially, relegated from the Premier League at the end of the 2003-04 season.
Their demise plunged to new lows when they were relegated to League One – England's third division – in 2007 before returning to the Championship in 2010, where Leeds have remained until this season.
Kisnorbo spent four years at Leeds between 2009 and 2013, playing a key role in the club's promotion from League One a decade ago, and the former Australia international told Stats Perform News: "A very big day for Leeds fans around the world, the club as a whole, the owners, players, coaching staff, coach.
"It's such a big thing for such a big supporter base. To get promoted to the biggest league in the world is a fantastic achievement. They've awoken a sleeping giant and it will be great for the game once the new Premier League season starts."
"They have such a massive supporter base," Kisnorbo said. "The atmosphere when you go to Elland Road or the travelling Leeds fans, no matter where they play, they always support the club. When you get to Elland Road, it's such a fortress. It's just great for English football.
"Hopefully now, Leeds can rebuild and stay in the Premier League."
Friday's result meant mission accomplished for highly regarded Argentine head coach Bielsa, who was lured to the fallen giant in 2018 following spells in charge of Argentina, Chile, Athletic Bilbao, Marseille and Lille.
Bielsa's trademark character and tactics almost resulted in promotion in his first season until Leeds faded, dropped out of the automatic places and lost in the play-offs.
Consigned to another Championship campaign, Bielsa and Leeds were not to be denied at the second time of asking, with famous stadium Elland Road – exiled from the Premier League for the past 16 years – back in the big time.
"He has come to Leeds with one thing in mind and that's to improve the club and team," Kisnorbo said. "He did it his way. People don't understand, it's hard. He worked the players really hard mentally and physically but the rewards pay off in the end. That's why is regarded as one of the best and that's why they were promoted.
"People don't realise how hard it is to be promoted from the Championship and he did it only through hard work, dedication and sacrifice. He demands everything from the players and you get rewarded like they have."
Kisnorbo, who now works as an assistant coach for A-League side Melbourne City in Australia, was named Leeds' Player of the Year in 2009-10.
The 39-year-old also helped Leeds stun fierce rivals and Alex Ferguson's Manchester United 1-0 in a famous FA Cup victory at Old Trafford, where Jermaine Beckford's winner sent the Whites through to the fourth round in 2010.
"It takes a special person to play for Leeds," Kisnorbo said. "There is such a high demand of pressure, when you play for that club, you have to give your all because that club for every supporter is their life.
"To understand what it's like is very difficult to explain in a lot of words because it's a feeling you have once you go there, it's a special feeling. There's not too many places that other teams don't like to go and one of them is Leeds. Why? For that fact that there's a group of supporters that just cheer their team on and for the players, it's built in you. It's in your blood. Once you step onto the pitch, it's 100 per cent for 90 minutes. It's just crazy."
Looking ahead to life in the Premier League, Kisnorbo added: "I'm sure Leeds will add to the squad but the players did the job, so maybe Bielsa will reward them because they all deserve it.
"Sheffield United [promoted to the Premier League last season and in contention for Europa League qualification this term] are a great example of a club who's done that. I'm not sure what will happen, I know Leeds will add to the current squad but there's every chance Bielsa will put all his confidence in the players who got Leeds to the Premier League."