"Fourth spot is up for grabs and we have two games in hand over many of our rivals, which is very important," said the 30-year-old Finland international.
"Last season we only finished three points off fourth place and we know it is only little details we can improve on. We are definitely going to give it a go.
"I don't know whether we will get that Champions League spot, but I know if we don't reach Europe, it's going to be a very disappointing season for us."
Jaaskelainen added: "We are a stronger side than last season when we finished sixth.
"And unlike last season we haven't had the kind of bad spell that we endured in November and December when we lost six successive games.
"But we learned from that and you can see that in the results.
"Also, over the past few seasons we have finished strongly and we firmly believe we can do so again."
In other news concerning the keeper, Sam Allardyce has indicated that Jaaskelainen is close to ending speculation about his future by agreeing a new deal at the Reebok.
"From what I can understand, Jussi is close to agreeing his deal" said the Bolton boss.
Meanwhile, Bolton midfielder Ivan Campo is set to feature in the club's end-of-season run-in - after recovering from his broken foot.
Bolton manager Sam Allardyce told the club's official website: "Ivan has got the all clear to start training.
"If all goes well he will join in with the rest of the lads and could be ready for the last eight games or so."