The only goal of the match came in the 83rd minute when Leandro Trossard found the net, securing a crucial win for Arsenal in their Premier League title push.
The result moved the London side five points clear of Manchester City as they continue their pursuit of a first English top-flight crown in 22 years.
The controversy erupted deep into stoppage time when West Ham believed they had levelled the score, only for the goal to be ruled out after a VAR review. Referee Chris Kavanagh was instructed by VAR official Darren England to check the incident at the pitch-side monitor.
The review focused on a challenge involving David Raya, with officials concluding that a foul had been committed in the build-up. After reviewing the footage, Kavanagh upheld the decision, disallowing the equaliser and confirming Arsenal's victory.
"Controversial. Due to, I think, the recent past of the Premier League, how it has been happening at corners, the blocks, and the holding," Espirito Santo told beIN Sports.
"So, I think everybody involved in football lost a little bit of perception what is or is not a foul - that's why we are upset. As in similar situations, there are different decisions.
"I don't quite understand. Sometimes it looks like a wrestling battle, so the concept of a foul is being driven away from what we used to see, and this leaves the players confused, leaving the crowd not understanding the reason behind the difference of decision."
Howard Webb has defended the controversial decision to disallow West Ham a late equaliser against Arsenal, insisting VAR made the correct call after identifying a foul on goalkeeper David Raya during a stoppage-time corner at the London Stadium.
The introduction of the VAR system in the PSL has moved a step closer after SAFA confirmed significant progress in its implementation plans.
Mikel Arteta praised the officials for making a "big call" after VAR ruled out Callum Wilson's late equaliser to secure Arsenal a dramatic 1-0 victory over West Ham United on Sunday.
Arsenal kept their Premier League title charge on course with a 1-0 victory over West Ham on Sunday, although the result was overshadowed by controversy after West Ham had a late equaliser ruled out.
