The Hammers goalkeeper feels that his side's Premier League clash against the Baggies is a vital one in their bid to avoid slipping further towards the relegation zone
The Hammers currently sit in 14th place with 33 points, just six clear of the drop-zone with nine games left to play.
Sunday's 2-0 loss at Chelsea saw Jaaskelainen's side drop two places and the Finn admits that the Blues could have won more comfortably.
|WEST HAM LATEST
|5/1||West Ham are 5/1 with BetVictor to finish in the Premier League top 10
"We just have to keep going. We have a weekend off now and then we have to go again in a massive game against West Brom in a fortnight."
The defeat to Chelsea was only West Ham's second game in March, compared to Chelsea's fifth, and Jaaskelainen admits that their lack of playing time has hindered their match-winning momentum.
"Sometimes you don't want to have a break and after the win over Stoke we thought it would be great to have a game the next week," he continued.
"Now we have another two weeks before our next match but that comes at a good time because we'll get three or four players back in and we'll be stronger. Hopefully we can benefit from that."