The Hammers have now kept clean sheets in four of their five Barclays Premier League games on the road.
Jaaskelainen told whufc.com: "Clean sheets are what we build from. It's not just me and the back four, it's the whole team, it's great for everybody in the squad because the first aim we have is to keep a clean sheet.
"I've not had a run like this [away from home] in my career, but it just tells you how well we work as a defensive unit. Maybe we just need to focus a little on our final ball and final finish and we'll be alright."
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