The Hammers took the lead in the first half through Manuel Lanzini, but the goal was reviewed at length by VAR due to the contribution of Jarrod Bowen. The forward appeared to be in an offside position as he ran across Leeds keeper Illan Meslier following a touch from Nikola Vlasic, with Lanzini picking up a rebound to fire home.
With Leeds chasing a leveller late in the second half West Ham broke to add a second, Bowen beating Meslier to seal a place in the fourth round for the hosts.
Bielsa's position has always been the same on referees and their decisions and there was no departure after Leeds' 2-0 defeat at the London Stadium. He believes it's the best course of action for managers to take in the interests of the game.
"It's a decision I prefer to accept what the referee's say, not because I don't have an opinion, I think it's a collaboration us coaches should make, to accept the decisions to the referees even if they jeopardise us," he said.
"If not we enter terrain where we can't offer what we want to offer, which is good football. There is a lot of arguments to say that the position I'm taking is incorrect, I consider them and I revise them but adding and subtracting I think the decision to accept their decisions helps their job and the spectacle. There are some conclusions that say the ones that demand the least would seem that it facilitates for the referee in case of doubts that they go towards the one that complains the least. I think the argument I'm offering is superior."
Bielsa had no argument with the result either, but felt Leeds should have made more of their possession in the final third.
"I think it corresponded that they won the game, they created more danger than we did," he said.
"They had balls with which to attack in worse situations than we did and they created more danger than us. In the second half there were things we improved, we pressed a bit better, we played in the opponents' half more time but in the end we should have created more chances than the ones we created. It would have been possible to prevent a lot of the chances they created."
Leeds were without Patrick Bamford, who was set to make his comeback from a hamstring injury until he suffered another knock. Bielsa is unsure what the exact problem is, but knows it's not muscular.
"Bamford recovered from the injury he sustained against Brentford and he was going to play again today, he was going to be the starter at centre forward and in the training during the week he suffered an injury that is not identifiable," said the head coach.
"It's a knock underneath his hip and it's still not clear what's the reason behind it. The only thing that's for sure is that it's not a muscular problem because his muscles are healthy."