Nuno kept his composure in his post-match interview with Sky Sports but made clear his frustration with the inconsistency of officialdom across recent seasons, suggesting the decision confirmed a pattern rather than resolved one.
"The way the game finished — we're all upset of course. I didn't pay attention to the replay just to not get more upset. But there's a referee, there's VAR, there's circumstances in the past that would be judged differently."
He expanded on his concerns about the wider standard of decision-making.
"Due to the recent seasons it's been happening — and even the referees don't know what is a foul and what isn't a foul. It creates a lot of doubt and speculation around it."
He was careful to place the result within a broader context, acknowledging the quality of his side's display.
"Let's look at the game overall. Before that we had a good chance. We made a good match — character, belief, how we played and went for it. Overall a good performance which in the end doesn't come away with the result we wanted, needed and expected. We lost the game. Finished."
On the tactical approach his side deployed, Nuno highlighted the role of his wing-backs.
"It was about being pragmatic — how to exploit weaknesses with our wing-backs. With the exception of the goal, we didn't allow much to Arsenal. Tough team we played against, the stadium was amazing — the noise, the energy. Thank you to the fans. It's our responsibility to bounce back."
West Ham United sit one point below safety with two matches remaining. Nuno was characteristically direct about the obligation ahead.
"We are on it. It is our obligation — the responsibility of defending a big club like West Ham."
Newcastle United at St James' Park is next. Tottenham Hotspur, who could drag West Ham further into trouble or give them breathing room depending on their result at Aston Villa on Monday, are being monitored.
"We watch every game. Let's see what happens. Time to rest and prepare well for Newcastle. Anything can happen."