A dangerous team with intensity, attacking intent, belief and incredible fitness levels - that's how Leeds have been described by some of the top coaches in English and European football.
Bielsa has made a huge impact at Elland Road since his arrival three years ago as he replaced the outgoing Paul Heckingbottom.
The Argentine head coach has taken Leeds from mid-table mediocrity in the Championship to the top half of the Premier League in his 36 months in charge in West Yorkshire.
Fans have come together across social media to thank Bielsa for his lasting impact on the Whites and wish him a Happy Birthday and we thought it would be a good time to take a look back at what his peers said about his team throughout the campaign just gone.
Bielsa masterminded a ninth-placed finish for Leeds following promotion last summer and impressed with with his attacking style of play in the top flight.
"I’m satisfied with what we achieved," Bielsa reflected on the season in May.
"It’s very difficult to win a game in the Premier League, very difficult, and, on the other side, I feel like we could have had a few more points.
"If we divided the competition in two, in the second part we received 50 per cent fewer goals than we did in the first part. Had we had that defensive security throughout the campaign, if we had added those points, I would have liked this season."
Here are some of the best quotes about Marcelo Bielsa' s Whites from Premier League bosses last season:
13. Sean Dyche
"They've been getting plaudits here, rightly so by the way, let's make that clear. And they've dug in, they've fought, they've done all the things you have to do."
14. Chris Wilder
"Huge football club, went toe to toe with them in the Championship and they are a brilliant addition to the Premier League. They're an exceptional team, well coached, a lot of good players."
15. Graham Potter
"They run so much and fight so much that we have to match them and be smart. We’re playing against a really good team."
16. Scott Parker
"They're a very good side. A unique side in the way they play and set up. You don't come across it a lot. The intensity with which Leeds play is always one you need to match."