"We have to be honest and say that there are tougher groups," he told BBC Sport. "The Scarlets have the toughest group, but there are no poor teams and no easy games in this competition.

"It's going to be tough but we have got a realistic chance. In saying that, I'm sure the other teams will think the group is wide open."

The Blues attracted a club record crowd of 26,645 at the Millennium Stadium when they hosted Leicester Tigers in the group stage of last season's competition.

Chief Executive Robert Norster said they are considering using the stadium for at least one of their home games against English opposition.

He said: "As has happened in previous years, if there's a window to use the national stadium to attract a big crowds such as playing an English team, that's something we will look at."

The Blues have never faced Bristol or Harlequins in the Heineken Cup, but lost both group games against Stade Francais in the 2004–2005 season. Young's side have never made it past the group stage of the competition.