The victory over the Hammers propelled Arsene Wenger's men back into the top-four in the standings, and the Sweden international - who has over 100 caps for his country - says that experience could prove key in trumping the Toffees.
"I think that my experience is one of the reasons why he [manager Arsene Wenger] bought me here," he told the club's official website.
"I have some experience and I felt quite comfortable going into my first game. It's nice to complete a game, it's a long time since I played so it was a nice moment for me.
"We got the win that we really needed to get back in a new pace for the final four games."
The North Londoners, who sit one point ahead of their Merseyside counterparts, continue their top-four bid with a visit to Hull City on Sunday.