The 28-year-old player had been seeking a move to St James' Park throughout the summer transfer window.
Wissa had expressed his desire to leave Brentford, even releasing a public statement to the media, highlighting his frustration with the situation.
However, he faced a setback when he failed to sign a crucial form, which could have jeopardized the entire deal.
Fortunately, a representative from the club was able to locate Wissa at the training ground and escort him to sign the form with just seconds remaining on the deadline.