The north London side claimed the three points at St James’ Park after goals from Granit Xhaka and Mesut Ozil wrapped up the three points for the Gunners.
Torreira has been settling into life at Arsenal since signing from Sampdoria in the summer transfer window.
The Uruguay international is still waiting to make his first Premier League start under new manager Unai Emery at The Emirates.
However, he came off the bench at half-time on Saturday and helped to inspire Arsenal to their third straight win in the Premier League.
And England legend Shearer feels that Torreira had a big impact on changing the game for the Gunners against the Magpies.
Speaking on Match of the Day, Shearer said: “They (Arsenal) certainly deserved the win, they were much the better team in the second half.
“Torreira made a difference when he came on at half-time. The difference that was he looked forward so quickly.
“Every time he got the ball his first thought was ‘Can I move it forward?’ and there was so much more movement ahead of him where there wasn’t in the first half. That was the big difference.”
Arsenal are aiming to at least try and break back into the top four this season after the north London side finished in sixth place and without a trophy last term.
The Gunners have not won the Premier League title since their famous unbeaten triumph in the 2003-04 campaign under Arsene Wenger.
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