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:
7. Carlo Ancelotti
"They play really well, they're a dynamic team, we knew this.They have a clear idea of football, create a lot of problems for teams they played against. It's a really, really good team."
8. Mikel Arteta
"They are a fantastic team, they put you under a lot of trouble and everyone knows their roles. Their energy level is incredible. It is difficult to maintain the physical demands of the game."
9. Roy Hodgson
"The fact that they never seem to stop running and they have the ability as a result to flood players forward because they seem to be able to flood them back as well - that is without doubt a quality.”
10. Ralph Hasenhuttl
"We know about their running stats and that they are one of the most energetic teams in the league."
11. Frank Lampard
"They are not easy to analyse but the stats say a lot of sorts, scoring against the top teams. Leeds are one of the most dangerous teams in the league."
12. Nuno Espirito Santo
"They broke us, created chances, they were so dynamic. We had to adjust and be more clinical in front."