As the game concluded around 11pm on Sunday night one customer at Albert's Shed, in Barker Street, placed a smoke bomb underneath a table before fleeing from the bar.
The situation led to the club being evacuated, the police and the fire service called, and now the hunt is on to find the man responsible.
Venue owner David Gregg said that the quick-thinking actions of manager Manon Houchett had prevented what could have been a far more serious situation.
Ms Houchett found the smoke cannister and she threw it out of the club's fire escape, stopping the venue getting completely filled with blinding smoke.
Albert's Shed had been full to its Covid capacity for the game, which England ultimately lost to Italy on penalties.
Mr Gregg said: "We were full for the football, as full as we can be for the seated audience, and as soon as the final whistle went someone took a smoke bomb out of their jacket, put it under the table and walked out.
"Thankfully Manon went and grabbed it and chucked it out of the fire exit."
The owner said that the smoke alarm was triggered and the building had to be evacuated.
Mr Gregg had been at the club's second venue in Telford when he was alerted to the news.
He said: "I was in Shrewsbury for the first half and it was a really good crowd. I went to Telford for the second half and just after the penalties finished I got a couple of messages saying 'the Shed in Shrewsbury was on fire'.
"I got the call from Manon saying everything was fine but someone had let off a smoke cannister."
He added: "The fire brigade were very complimentary to her and the staff for how they handled the situation, and were quite happy with what they had done."
Mr Gregg said that they were studying CCTV with the aim of getting the individual responsible banned from licensed premises in the town.
He urged anyone with information to get in touch, saying: "We are asking for any information about who did it with a view to getting them banned."