The Belgian winger scored the only goal at the London Stadium in the 23rd minute, converting Martin Ødegaard's incisive run and pass with a precise finish into the corner. It proved to be the difference between two sides separated by everything in terms of their position — Arsenal fighting for the title, West Ham United fighting for survival.
Trossard spoke to BBC Radio 5 Live after the final whistle, reflecting first on the tension of the afternoon.
"Joy. We knew what we had to do today, and that was to take three points. It was tough — we knew up front what they were playing for and they put up a good fight. It is so nice for us to get three points here and go home with a win."
When Wilson's header crossed the line in the 95th minute, Trossard said he was inside the penalty area and could not immediately tell what had happened.
"A lot happened, as you could see. At the first moment I did not see what happened with the foul on David Raya because I was in the pack as well. He was quite convinced that it was a foul, so I was quite relieved in that moment. I thought it was a foul but in that moment you are never sure what the referee and VAR are going to do. From the moment he said it was a foul, I was obviously really relieved."
He also offered his read of the protocol that governs such decisions.
"Most of the time you know it will go in your favour if they go to the monitor because it means VAR have seen something. It should be a foul."
On his goal, he singled out the assist.
"It's an amazing run from Martin. He does so well to get the ball to me, and then just in that moment I put all my power and precision on the ball to get it into the back of the net. It was such a relief to score that goal."
He was measured when reflecting on what lies ahead.
"I don't need to explain what is at stake — everyone knows. Two very important games for us. We have all the belief that we can do it, but we have to work hard to get three points in the next games as well."
Arsenal are five points clear of Manchester City with two matches remaining. City have a game in hand.