The triple Heineken Cup winners will enjoy home advantage at their Dublin base against the defending Amlin Challenge Cup holders but centre Gordon D'Arcy is well aware of the threat Yachvili poses.
"Predominantly, with the teams we are used to playing, the No 10 will be the playmaker but he is very much the man who dictates everything," said D'Arcy.
"You just do your homework on them - and Joe has a few ideas in his head and he shouts them at us - so hopefully we can implement them and try to nullify the threat.
"But he is a major player and if you look at how he pulled the strings in the quarter-final at Gloucester he just seems to have an endless amount of time on the ball.
"Generally the rule is that the further along you get the tighter the game is so the 40-yard pass that Yachvili threw over the top against Gloucester may not be thrown this week but you never know. We know they definitely like to play rugby and they are well able to do that.
"And it does feel like a European week. There is three times the amount of media here and there is that little bit of tension around the squad, unless somebody does something to lighten it. There is definitely a good buzz around the place, no doubt about it.
"We wanted a European trophy this year and having that massive card of playing a semi-final and a final at home was a big drive for the Wasps game."