Gabriel Magalhaes enjoyed a dream Arsenal debut as he got on the scoresheet.
The Brazilian defender rose highest from a second-half corner to nod the ball in from close range and put his side 2-0 up.
He did not catch his header cleanly, with the ball appearing to strike his shoulder before finding the net.
There were no doubts as the goal was given and VAR did not intervene as Gabriel celebrated a memorable moment.
But his joy might have been short-lived last season.
The ball striking his shoulder could have been deemed a handball under previous guidelines, which were altered ahead of the new season after some controversial decisions last season.
Instead, the ball must now strike the arm below the shoulder, or the cap of the sleeve, meaning Gabriel’s goal was allowed to stand.
Former Premier League referee Dermot Gallagher explained to BT Sport: “I think last season it could possibly have been disallowed.
“This season, the below the arm pit, ie. the cap of the sleeve, it definitely did not strike him below that.
“Goal given quite rightly and illustrates the new change.”
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The new handball rule, installed by IFAB and used by the Premier League, now states: “For the purposes of determining handball offences, the ‘arm’ stops at the bottom of the armpit.
“Accidental handball by an attacking player should only be penalized if it ‘immediately’ results in a goal or an obvious opportunity for the player and/or their team to score a goal (i.e. following the handball, the ball travels only a short distance and/or there are very few passes).”
Gabriel was not the only Arsenal debutant to impress with fellow Brazilian Willian also putting in a fine display.
Speaking about the pair ahead of the game, manager Arteta said: “They’ve been training really well. They’ve been adapting quickly, they are really excited to be here with us. Really good energy from both. Big talents, both in very different phases of their careers.
“Someone [Willian] that is already very established in the Premier League with an incredible quality and another one [Gabriel] that has to adapt to this league but has huge potential to become a key player for us in the future.”
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