Belgium coach Marc Wilmots is targeting a "lack of balance" in Argentina's ranks as the two sides prepare for their World Cup quarter-final showdown on Saturday.The Red Devils advanced to the last eight of the World Cup for the first time since 1986 on Tuesday with a battling extra-time victory over the United States.That Belgian campaign 28 years ago ended in the semi-finals, when an Argentina side inspired by Diego Maradona defeated them 2-0 in the Azteca Stadium.Parallels with that meeting have been drawn in Brazil, not least because Argentina so far have been heavily reliant on captain Lionel Messi.Wilmots, who has yet to experience defeat in a competitive match since he took over at the helm in 2012, spoke admiringly of Argentina but is confident the South Americans can be attacked."I saw three central defenders, two fullbacks who play very high, (Angel) Di Maria and (Ezequiel) Lavezzi, (Gonzalo) Higuain and (Lionel) Messi," said the 45-year-old coach."But I also feel there is a lack of balance in that team."For once we're not favourites but I don't mind. Once you're in the quarter-finals the only thing that matters you want to go all the way and that is what we want to do."Wilmots meanwhile said he believed Belgium would cause problems for Argentina, and insisted he would not focus exclusively on stopping Messi."We won't only be watching Messi -- we'll deal with this Argentina team as a whole," he said. "Switzerland did very, very well. And we play the same way from forward to back. I don't know how they will adjust to our game."So we have to be creative. But I want to see what they will do to trouble us."