Ireland captain Brian O'Driscoll is an admirer of Wales' attacking approach but warns their RBS 6 Nations title challenge could be dealt a blow at Murrayfield.
The March 19 fixture between Ireland and Wales is shaping up to be the Grand Slam decider but both nations have one more hurdle to negotiate before setting up the winner-takes-all clash in Cardiff.
Eddie O'Sullivan's men face France on Saturday at Lansdowne Road while Wales must overcome Scotland in Edinburgh on Sunday.
Wales have emerged as the Six Nations' form team and have provided plenty of entertainment in the process with players such as Shane Williams and Gavin Henson taking centre stage.
Although O'Driscoll has been impressed by the manner of their elevation to serious championship contenders, he believes they may find wooden spoon candidates Scotland a tougher challenge than expected.
''I have been excited by Wales throughout the tournament. When questions have been asked of them, they have stepped up to the plate - especially against France,'' he said.
''Their backs are in great form and we have seen some lovely movement from them.
Wales' threequarters have thrived on the confidence that winning has brought them. A confident Wales side is very dangerous.
''But I think they will be surprised at Murrayfield because I expect a big performance from Scotland. Scotland have struggled but Wales certainly will not have it all their own way.''
England Under-20s head coach Martin Haag was full of praise for his World Rugby Under-20 Championship-winning side after Harry Mallinder inspired them to a 45-21 win over their Irish counterparts and a third title in four years.