Arsenal were put in the strange position of being allowed to use four substitutes in the Premier League game against Newcastle.
That was down to the Premier League's concussion rule, with Newcastle defender Fabian Schar being forced off early in the second half due to a head injury. As a result, both teams were then allowed to use four substitutes in the match at St. James' Park.
It was a decision that Mikel Arteta did end up coming to, with Takehiro Tomiyasu suffering an untimely injury right before half-time. The Japanese full-back went down clutching his hamstring before being replaced by Cedric Soares.