|BDO World Championships 2015|
|Date:3-11 January 2015Venue:Lakeside Country Club, Frimley Green|
|Coverage:Watch live on BBC TV, online, mobiles, tablets and BBC Sport app|
Robbie Green says he will have to improve his level of performance if he is to beat Lakeside giant-killer Peter Sajwani at the BDO World Championships.
Green, 40, will face Swedish supermarket manager Sajwani in the last 16 after beating Lithuania's Darius Labanauskas 3-1 on Tuesday.
Qualifier Sajwani eliminated top seed James Wilson in round one.
"For him to come back after what James did shows he's got grit - he's going to be a tough player," he told BBC Sport.
"Obviously I'm going to have to improve on my match against Labanauskas but that's the way you get into the tournament.
"I can play a lot better than that but I'll take it."
Wallasey-based Green has been struggling with a knee injury in recent months and is managing the problem as he looks to better his run to last year's semi-finals.
"I have to work out what practice I do," added the 16th seed.
"I did a good session the other night with [fellow BDO player] Paul Hogan and I was supposed to have another session with him on Monday, but I couldn't do it. I got up in the morning and it was really tight.
"I didn't want to overdo it, so I did 10 minutes here and 10 minutes there, just to try to loosen it up a bit.
"It's been fine today. I wouldn't put the performance on my knee, it just wasn't spectacular."