"Danny Welbeck is getting sharper, because he has been out for a while", said Wenger.
Wenger introduced Wilshere in place of Reiss Nelson, who faded on his first Premier League start but a goal from the visitors felt inevitable.
Arsenal manager Arsene Wenger praised his team for having the third best home record in the Premier League earlier this week, and his side kept up their impressive form at the Emirates today with a 3-2 victory over Southampton.
At the Emirates Stadium, Southampton defender Jack Stephens was shown red in injury time when he reacted to Jack Wilshere tugging his shirt by pushing the Arsenal midfielder to the ground.
And they look well-set to save themselves from relegation as Hernandez's strike moved David Moyes's men six points above the drop zone in 14th.
Substitute Charlie Austin equalised a minute after coming on but with nine minutes left Welbeck headed in Iwobi's cross.
Hart produced a brilliant flying save to deny Marcos Alonso a winning goal.
"I am very pleased for him because he is a guy who went through a very hard time and has shown exceptional mental strength to come back", said Wenger.
"He had every reason to feel sorry for himself, to think the mountain was too big to climb, because it was the right knee, then the left knee and a year out every time".
"People questioned whether he would come back and he continues to go".
Welbeck was the hero for the host, the forward on hand at the back post to nod home Alex Iwobi's deep cross for the victor just moments after he had failed to convert a glaring opportunity inside the six-yard box. "I know when I get the opportunities in front of goal I will put them away - apart from the one I put over", said Welbeck.