"They will be a major challenge for us - it's no accident that they've been as successful as they have been - we need to understand that success and create a style of rugby to challenge it which is what we've been working on and I have every certainty that we have the confidence, self-belief and physicality to challenge for the trophy on Sunday," he told the Scarlets website.
"They're a formidable side to play against, with a unique defence which has been very effective for them over the last seven or eight years. Home advantage is everything and Twickenham is home for the Wasps.
"In our away fixture at the Causeway Stadium before Christmas we were second best by a long way. There were a number of reasons for this - we'd struggled with selection, then we lost Simon early on, which was closely followed by a sin bin and before we knew it we were 27 points down and never able to get back into the game.
"It was one of Wasps best performances this season, we've watched the video of that and other games and learnt from them - we're hopeful that Sunday won't be a replay."