Leicester have lost six of their last eight games in all competitions, culminating in an embarrassing FA Cup elimination to third-tier Millwall on Saturday.
They sit one point and a place above the Premier League relegation zone and are without a league win in 2017.
"We just have to completely forget what happened last year. We need to work hard each and every single one of us, the staff and players and come game time it is up to us when we step over the white line," Vardy told a news conference ahead of Wednesday's clash in Spain.
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"It has been tough, things haven't clicked this year, but we know if we keep giving 100 percent for each other things will change."
While Vardy admitted little had gone right for the unlikely champions in domestic competition, he said he was looking forward to the temporary distraction of facing Sevilla and hopes a good result could kickstart Leicester's campaign.
"It's a game where we can just forget about that (their domestic struggles) for one night and hopefully if we get a good performance we can use that to kick on and pull ourselves away (from the relegation zone)," said the England international.
"We've played better in the Champions League but for some reason it has just not clicked in the Premier League. I wish I could put my finger on it myself to change that around but obviously it's not been that easy."
Having lost their last two games to fellow Premier League strugglers Swansea City and lower league Millwall, Leicester would be forgiven for feeling daunted by the prospect of facing Sevilla.
Jorge Sampaoli's side are third in La Liga and have thrilled onlookers with their brand of lightning-quick, ultra-attacking football this season.
Leicester manager Claudio Ranieri heaped praise on the Europa League holders, who have won five European trophies in the last decade, and confessed his love for the city of Seville, the scene of a King's Cup triumph when he was in charge of Valencia in 1999.
"Ten years of triumphs means the club (Sevilla) is doing well, they change coaches and the club is still doing well. Jorge is having a great season," the Italian said.
"It's the first time we've won a title and the lads have dipped a bit. But tomorrow we have to fight with our heads held high, chests out."
(Reporting by Richard Martin; Editing by Toby Davis)
